# subZero: A proven method of starting and running a planted tank



## niko

What you are about to read will be overwhelming for most readers. But in fact, the principles are very simple. If you try to understand the idea you will see that it is VERY SIMPLE. You wil have a completely algae free tank full of lush plants. Guaranteed. But I believe that is not the best way to run a planted tank.

This post presents principles and critiques them very clearly. It is what the planted tank hobby in the US desperately needs. Not a receipe ready to go, but a logical approach that opens up the door for more exploration and understanding.

The method described here was developed about 5 years ago. I called it "*subZero*" because seemingly there are no fertilizers present in the tank. But they are there, just in minute amounts. Of course you cannot have a negative concentration of fertilizers - but the name "subZero" is a direct attack against the trend to keep the nutrients in excess like the 2 other imperfect methods (EI and PPS) advise.

SubZero is a method of starting and running a planted tank that is more efficient than EI and PPS. Just like them it fails to look at the tank as a system. It basically focuses on the plant nutrition and very little else. That's why it is more appropriate to call all 3 methods "methods". In quotes.

(_*Scientific method:* a series of steps taken to acquire knowledge._ But with EI, PPS, or subZero we get results by ignoring many steps and focusing only on what we consider essential.)

So, all 3 "methods" choose fertilization as the tool to start, control, and run a planted tank. All achieve very good results. Actually exceptional, but with severe limitations. subZero is the best but no less limited. What is different about subZero is that it intentionally leads the tank to a state of true stability without any large fluctuations in the tank state along the way. At the final state the tank does not need any maintenance apart from refilling the evaporated water and trimming the plants.

_(You can let the water evaporate half way. Never fertilize or feed the fish. Run the lights as little or as long as you care. Go on vacation without changing anything about the tank. Algae never, ever, develops and below you will understand why. CO2 is used in minor amounts, but from what I've seen has a profound effect on the survival of many plants. When a subZero tank runs out of CO2 some species of plants die within 2 days. That, to my knowledge, is the the only drawback of the subZero "method".)_

From what I know about ADA's method (note that it is not a "method" in quotes) subZero is based on very similar principles. Simply put - the nutrients are available but "hidden". Except that ADA does things with the entire system in mind (substrate, water parameters, flow, filtration, light, CO2, O2, tank stage) while subZero and the other "methods" account very little for most of these things.

Applying subZero is very simple. But *you MUST be consistent in the first 2-3 months*.

*SubZero "method" basics:*
Nutrients are the main tool to control the plant's growth and health.
The nutrients are added in gradually increasing concentrations until enough concentration is reached but there is no excess.
The nutrients are available to the algae for a very short time (often 1-2 hours only).
The nutrient availability is so preciesly controlled that you have a guaranteed way to (every single time!) handle algae problems (if they ever arise!).

*How it's done in real life:*
First off - I have not tested this "method" in any other water but water with KH/GH of 3-4 and pH of 7-7.2. But the "method" is completely customizable as can see below.

So we will be saturating the water with nutrients in an amount that is "enough" but never in excess. What is "enough" we cannot say in numbers, spoons, ppm, or mg/L. Te plant growth is the only guide. This could be worded as "Feed progressively more until you see good growth. Maintain that level of fertilizing forever":

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*WEEK 1*:
Day1: 
Setup the tank. Normally the plants exibit an explosive growth the first 3-5 days. I guess there are micronutrients in the newly setup tank. They are depleted very fast.
Day 3:
10-20% water change (WC).
Day 4-5:
Plants stop growing. This is a guaranteed event.
Day 5:
After a WC add 1 gram Potassium + 1.0 gram Calcium.

*WEEK 2*:
Day 7:
Observe the plants - do they show good growth. Most likely not.
WC. 
Add [1 g K] + 1.0 gram Ca.
Day 9:
Observe the plants - do they show good growth. Most likely not.
WC. 
Add [1 g K] + 2.0 grams Ca.
Observe the plants - do they show good growth. Most likely not.
Day 11:
WC. 
Add [1 g K] + 3.0 grams Ca.
Observe the plants - do they show good growth. Most likely not.

*WEEK 3*:
Day 14:
At this point is obvious that the K + Ca only do not do anything worth noting. 
Look at this in a simple way: You are adding a visible amount of K + Ca in 55 gallons of water. This K + Ca are floating in that water for sure. They are available to the plants for sure. There is no need to add more and more. It is clear that we need to add something else!
The next thing we add is Magnesium. Meaning that we continue to add the [1 g K + 3 g Ca] AND start the same progression with the Mg.
WC.
Add [1 g K + 3 g Ca] + 1.0 gram Magnesium.
Day 17:
Observe the plants - do they show good growth. Most likely not.
WC. 
Add[1 g K + 3 g Ca] + 2.0 grams Mg
Observe the plants - do they show good growth. Some maybe. Most likely not very good.
Day 20:
WC. 
Add [1 g K + 3 g Ca] + 3.0 grams Mg
Observe the plants - do they show good growth. Some maybe. Most likely not very good

*WEEK 4*:
Day 21:
It is obvious that the K + Ca + Mg only do not do much to improve the growth. Plants are growing and healthy more or less but not great.
Look at this in a simple way: You are adding a visible amount of K + Ca + Mg in 55 gallons of water. The K + Ca + Mg are floating in that water for sure. They are available to the plants for sure. There is no need to add more and more.
It is clear that we need to add someting else too!
Next thing we add is Nitrate. Meaning that we continue to add the {1 g K + 3 g Ca + 3 g Mg] AND start the same progression with the Nitrate.
Except that we add the NO3 in smaller amounts than the Ca and Mg. (3 grams of NO3 is a huge amount. We start with 0.1 gram and progress to 0.5 grams)

WC.
Add [1 g K + 3 g Ca + 3 g Mg] + 0.1 grams NO3
Day 24:
Observe the plants - do they show good growth. Most likely not.
WC. 
Add [1 g K + 3 g Ca + 3 g Mg] + 0.3 grams NO3
Observe the plants - do they show good growth. Most likely not.
Day 27:
WC. 
Add [1 g K + 3 g Ca + 3 g Mg] + 0.5 grams NO3
Observe the plants - do they show good growth. Most likely not.

*WEEK 5*:
This is where it starts to get interesting. The plants actually start to grow very well. Algae are non existent. Ca, Mg, and NO3 test at zero. But you KNOW they are in the tank! ...Hence the name "subZero".
Ok, same thing all over again. This time with Phosphate:

Day 30:
WC.
Add [1 g K + 3 g Ca + 3 g Mg + 0.5 g NO3] + 0.1 gram PO4
Day 33:
Observe the plants - do they show good growth. Yes! But it is not really good.
WC. 
Add [1 g K + 3 g Ca + 3 g Mg + 0.5 g NO3] + 0.3 grams PO4
Observe the plants - do they show good growth. Yes. And what's more important - we see a definite pick up!
Day 36:
WC. 
Add [1 g K + 3 g Ca + 3 g Mg + 0.5 g NO3] + 0.5 grams PO4
Observe the plants - do they show good growth. Yes. VERY good growth.

*WEEK 6*:
This is where we get into fine tuning with Iron and Traces. The plants grow just fine but we need to make the most of the "method". Without Fe/Traces we KNOW the plants will stunt at some point. Some will not grow at all anyway. Algae are non existent. Ca, Mg, NO3, PO4 test at zero. But you KNOW they are in the tank! (SubZero.)
Ok, same thing all over again. This time with Iron/Traces:

Day 39:
WC.
Add [1 g K + 3 g Ca + 3 g Mg + 0.5 g NO3 + 0.5 g PO4] + 0.1 Fe/Traces
Day 42:
Observe the plants - do they show good growth. Yes! Very good.
WC. 
Add [1 g K + 3 g Ca + 3 g Mg + 0.5 g NO3 + 0.5 g PO4] + 0.1 Fe/Traces
Observe the plants - do they show good growth. Yes! Very good.
Day 45:
WC. 
Add [1 g K + 3 g Ca + 3 g Mg + 0.5 g NO3 + 0.5 g PO4] + 0.1 Fe/Traces
Observe the plants - do they show good growth. Yes! Very good.

This is it. Done! The magic amounts of fertilization are:
[1 g K + 3 g Ca + 3 g Mg + 0.5 g NO3 + 0.5 g PO4 + 0.1 Fe/Traces]
Depending of water changes + uptake you may or may not be able to test for them - subZero.
But what is more important - you have taken the tank GRADUALLY to that level. It has become accustomed to this final state very gradually. That means stability.

Use the same [1 g K + 3 g Ca + 3 g Mg + 0.5 g NO3 + 0.5 g PO4 + 0.1 Fe/Traces] in the first week of the tank setup and you KNOW you will get in big trouble. I hope my point is clear to you - planted tanks have stages and you must consider them!

You are not really done actually. There are still about 6-10 months of development behind the scenes. Meaning the tank will look and be predictable but it has not reached the state of true stability.
After that period you will have a tank that has it's own balanced life. Guaranteed. You are free to go on vacation now and just wave the tank good bye!

At Week 6 your tank is completely manageable. There is a definite answer how to handle any algae:
If ANY algae manages to appear you immediately do 1 to 3 water changes. Every day about 20%. And do not fertilize at all. The nutrients concentrations drop to such low levels that your plants stop growing. But they have storage mechanisms that will take them through a period of bad starvation. They will not grow but they will not die. The algae has very little stored reserves. After 3-5 days you resume the maintenance fertilization ([1 g K + 3 g Ca + 3 g Mg + 0.5 g NO3 + 0.5 g PO4 + 0.1 Fe/Traces])

As you see - the nutrients are available but "hidden" for the algae. They get used up so quickly and efficiently by the plants that the algae simply does not have time to steal some food. ADA also hides the nutrients but it does it as an inherent part of their system. They make use of all the other factors in the tank. SubZero, EI, and PPS play with fire by maintaining excess nutrients in the water. SubZero is the most careful but still does not make use of the other factors in the tank.

The only algae that resist the "low nutrient warfare" is Cladophora. But everybody knows that smooth tank maintenance with great growing plants will eventually wear off all algae. That is true for Cladophora too. BBA is not a challenge at all. Once again - IF algae appears you have a definite and guaranteed weapon against them.
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Now please note once again that in that 6 week desription there was no mentioning of any light, filtration, CO2... You see the downside of the "method". That is exactly what EI and PPS do too. If you believe that's the right way to run a natural system I have nothing to say. All 3 "methods" work but basically rely on things falling in place by themselves eventually. There is no real understanding of the interaction of the parts of the system. EI and PPS are not concerned with the long term establishment. They are happy to provide amazing looking clean tanks for you and they do it in a peculiar, partial way. subZero does the same but at least has a final goal in mind.

--Nikolay


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## JustLikeAPill

See... people complain that they don't know what's in the ADA line of fertilizers or exactly how they work...

Then you make this which accomplishes the same/similar thing. I have a feeling a lot of those people who want hard core numbers will just buy the Brighty series after this if they want to try the "subZero" method ; ) That's a lot of stuff to read! Maybe better to just add 1 squirt per 20 liters of water and call it a day...

Thanks for the time and effort! Interesting read.


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## niko

I know!

haha

Look what I just said here:

http://www.aquaticplantcentral.com/forumapc/water-bucket/78221-money-hobby-11.html#post599535

Also... Yes most people will not really want to know how it works. But many follow PPS which no less complicated, except gives you a "to go" portion of questionable quality.

Also... It does appear that ADA has some marketing geniuses there, right? Not too many details, uber cool looking products, step-by-step (no detail) instruction. I think we all start to see the beauty of the marketing approach.

--Nikolay


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## countcoco

Great post! I think you should remove the part about your method being overwhelming to beginners since it's incredibly simple and overall requires very little maintenance. 

My only real question is whether you have tested this method with inert substrates or nutrient rich ones like aquasoil? I personally believe the ADA "method" is the best approach in tanks with aquasoil or similar nutritive substrates, but I feel it would be less effective in plain sand, gravel etc, especially if the tank contained a lot of nutrient hungry plants (eg riccia, hc, hygros, etc).


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## fishyjoe24

I'm going to have to try this, and see how it works out......


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## wearsbunnyslippers

hey niko,

you have not specified if this is for a 1 gallon or 100 gallon tank, surely the amounts you add will be different based on tank size?


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## pat w

Reread the day 21 entry. A 55g water column in stated.

Any way to convert to this method?


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## niko

Coco,

In the light of the recent conversations in which you have been a part of I believe that the majority of hobbyists that do not understand much will not try to understand something that seems complicated. What I wrote here is indeed simple - IF you actually read and try to undersand it.

I just redid the beginning of the original post. Tried to keep it in line with the goal of the post. And not sound like I'm on my way to make subZero popular. That is definitely not my goal.

I'm not going to follow Tom's active approach to make subZero popular. I know enough how to push it if I wanted to and get some number of followers. But in the last 6 or so years I've been in this hobby trying to find more understanding. I've grown to hate mediocre knowledge. Note how I wrote the first post here - clearly stating that it's a step toward more, deeper knowledge.

I remember some years ago talking to Edward about his newly hatched PPS. He was getting opinions how to best present it to this community. We talked about having to be on the forums constantly for several months and answering every single question. And he did exactly that, than removed himself and let PPS roll. I'm not doing any of that. If someone wants to try subZero or ask me questions -fine, I'll answer all "complicated" questions. And I'm not going to ever say anything different from what I said here - subZero works AND it is an example of a partial approach to running a planted tank, just like EI and PPS.

*EI, PPS, subZero = duct tape + chewing gum to fix your car.* Yes they all work very well. The car it will run. That cannot be denied.

To answer your question:
When I came up with subZero I used only pool filter gravel - inert substrate. 
Once again - look at the downside of all 3 "methods" - they all could care less about anything but fertilization.

WearsBunny,
Yes, as Pat said - I gave an example with a 55 gal. tank.
But be aware - the actual grams of dry chemicals maybe diffferent. Here I picked easy to read numbers. The idea is to understand that you:

1. Add the initial dose of any chemical in an amount that will not do anything. But you have to start from somewhere.

2. Gradually raise the amount to where it should affect the plants. If it doesn't - that tells you you need something else too.

Converting to subZero
Don't understand what that means. One guy messaged me that he may try to actually get off EI by gradually scaling down his fertilizers and gradually bringing the tank to a subZero state. That will be interesting as an experiment.

--Nikolay


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## MiamiAG

Niko,

Thanks for this. I think it can be boiled down to simple steps that Amy newbie could understand.

Regards,

Art


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## countcoco

So is the underlying method/theory independent of substrate type???


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## krisw

countcoco, I would say it would have to be. Using this with Flourite/EcoComplete, you would operate just like described. With ADA Aquasoil, your plants grow pretty darn well for 3-6 months. Then, certain nutrients deplete, often K is the first thing that needs to be supplemented. By about a year, I think, the subZero approach would level off. 

My question is the bit on going on vacation. I assume that you're saying that once you've figured out the required minimum dosing levels, you need to setup an auto-doser to dose those things while you're on vacation?


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## JustLikeAPill

He is saying you can go on vacation and forget about it.


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## krisw

That's what I thought. So, how does that work? If you're supplying the minimum number of nutrients for the system to grow, wouldn't it bottom out, causing plants to quit growing, and if long enough a break, begin to starve? I have some experience in neglecting tanks, and this is often the case. 

Overall, I very much agree that finding the sweet spot for dosing in your tank and consistently sticking to that provides great results. I also agree that the plants can be better indicators of tank health than any test kit. The suggested method for finding that sweet spot makes a lot of sense, and is pretty straight-forward. I just wonder about the lack of water changes and vacation claims.


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## JustLikeAPill

By the time the tank is mature and can be left alone, there should be a lot of crap that has built up in the substrate that should sustain them over a vacation. 

I guess.


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## niko

I have no explanation why at some point the tank becomes completely stable. Almost self sufficient. Actually... yes, self sufficient.

Here's a picture of such a tank. Horribly neglected:
https://picasaweb.google.com/ddasega/Simple#5630718501934716818

The plant that grew best was Valisneria nana. That is not a run of the mill Valisneria. Try to grow it without CO2 and see. In this tank the V. nana has taken over completely about 3 times in the last 3 years. I have no idea why. There is not even CO2 at all times. The growth severely slows down if the duckweed covers the surface. Other than that - I've had this tank evaporated down to 60% and there are no issues. Other plants are mosses, E. tenellus, Pellia, Najas "Roraima". Before these plants the tank was chock full of Hygrophilla angustifolia. Try growing that with bad CO2 and no ferts. When I gave it away it filled 3 grocery shopping bags!

Once again - I'm not trying to sneak a new imperfect "method" into popularity. What is the most important of all this subZero observations/approach is that if a tank can become completely stable somehow it would be great IF we knew how to make that happen ourselves.

--Nikolay


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## Bert H

NIko, nice write up. Did I miss it, or do you mention the lighting/duration anywhere here and how it would affect your method?


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## niko

The point is to show how partial EI, PPS, and subZero are. They seem to completely ignore light, filter media, substrate, etc.

With subZero I used to run the lights 10-11 hours a day straight. Average of 2 wpg. Of course you are free to adjust anything you want.

Once again - the emphasis is on fertilizers - they make the tank, they break it.

--Nikolay


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## krisw

Niko, actually I think your lighting situation contributed greatly to the stability you've experienced. I have a similar situation on my 75G. It has 2 WPG of PC (AHSupply) lighting, using several year old Aquasoil, which I dose minimally by eyesight, based on how the plants look. Compared to my other tanks which have newer HOT5 lights, it's far more stable. The lights don't drive the plants to grow crazy fast so the nutrient requirements are fairly small, and I suspect that the nitrogen sink (I mean canister filter), combined with organics in the older substrate help to sustain plant growth when I go on vacation. I'm pretty confident that if I switch the light to a four or six bulb HOT5 fixture that I'd destabilize the tank significantly. 

I've often thought that newer brighter fixtures have made things more difficult for people because they're super-sizing the amount of light going into their tank beyond what the plants actually need, creating a much larger requirement for CO2 and nutrients, leaving less room for error.


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## niko

The answer to higher light in all 3 "methods" is: Increase the fertilization.

And it works. I said that my tanks that I experimented with subZero where an average of 2 wpg. One was 3.5 wpg. I can't say that the need for nutrients was much more, but it was higher - the "magic" formula was the same as described above but with higher N, P and Fe/Traces. 

I don't remember how much higher. But it as not much more than a 1.5 wpg tank. 

--Nikolay


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## tokyo

I don't mean to speak out of turn(having a complete lack of experience and not being a member of your club), but I have a couple questions.

1:
How did you arrive at [1 g K + 3 g Ca + 3 g Mg + 0.5 g NO3 + 0.5 g PO4 + 0.1 Fe/Traces] as the "magic number" for fert quantity? Just trial and error? Existing knowledge/experience?

2:
How would you go about scaling this to a different volume? I would assume you could probably just maintain the fert/water ratio. Thoughts?


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## niko

The numbers are examples for a 55 gal. tank.

I would not write all this if I have not tried it. In about 5 tanks, diffferent sizes, plants, lights.

It works.

The idea of subZero is, once again, to gradually increase the fertilization to a level that's reasonable but not excessive. You can start with your own numbers and arrive to your own "magic" formula.

And the idea of this thread is to make you think about "methods" that work but are not exactly right. Meaning that you are doing the work. With subZero at least the goal is to have a completely hands off tank with the least issues (if any) from day 1.

By the way - after about 6 weeks the water changes are only once a week. The tank enters a seemingly stable state at about week 6. The bi-weekly water changes are not needed any more. Unless algae appears - which is 1. Highly unlikely. 2. You have a way to stop it every time, guaranteed.

Just remember - a true stable state is achieved after the 8-th month. ADA, EI, PPS - that is how it is, folk!

*I'm starting to think that if subZero seems simple to many people it's not a bad idea to support it here on the forum. Because from what I see a simple approach to running a planted tank is desperately needed in the US. Simple and guaranteed. The hope is that people will start thinking about better methods that see the aquarium as a system. Not just a vessel to dump chemicals in.*

So I will be answering any questions. Just please if you are trying subZero keep in mind - it is all common sense. You will not hear anything from me that isn't something you can figure out by yourself.

--Nikolay


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## tokyo

niko said:


> The numbers are examples for a 55 gal. tank.
> 
> I would not write all this if I have not tried it. In about 5 tanks, diffferent sizes, plants, lights.
> 
> It works.
> 
> The idea of subZero is, once again, to gradually increase the fertilization to a level that's reasonable but not excessive. You can start with your own numbers and arrive to your own "magic" formula.


I did not mean to appear as though I was questioning or doubting your numbers or method. The question was more a result of curiosity. I am curious about the process you used to achieve these numbers. I feel like it would be a helpful piece of information for anyone looking to experiment with your system.

Thank you for your response. Contributions like this make it so much easier for people, such as myself, to break into this hobby.


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## niko

Tokyo,

And I didn't respond as if I was offended. Just stating how I came up with subZero back then.

Best person to ask about scientific level experiments with plants/fertilizers is Tom Barr. Find his forum if you want and become part of a large group of followers of EI (Estimative Index).

About the "process" to come up with subZero:

Look at every step and you will see that it's always the same thing:
*"Can I deny that?"
"No."*
"What do I do next?"

The following monologue will surely seem dumb to some folk. I'm making a point with it. The point is to show how you can be critical with what you do to your own planted tank. Not someone else telling you what to do over the internet. *It's YOU that make the decisions*:
_
"How much Calcium should I add as a first dose?"
"Have no idea. But it must be a safe amount."
"How much is a "safe amount"?"
"Have no idea. But 1 gram Calcium in 55 gallons of water is definitely very little."
"Can I deny that?"
"No."
-->"Start with 1 gram."

---After gradually increasing Calcium to 3 grams:---
"Is 3 grams Calcium in 55 gallons of water too much?"
"Have no idea. But I know for sure it's in the tank now. It's got to be available to the plants."
"Can I deny that?"
"No."

"Do the plants grow."
"No."
"Can I deny that?"
"No."

"Do the plants need something else?"
"Have no idea. But Calcium only does not do anything."
"Can I deny that?"
"No."
-->"Add something else."

"What to add next - Mg, NO3, PO4, or Fe/Traces?"
"Magnesium is the safest of them all."
"Can I deny that?"
"No."
-->"Add Magnesium."

--For the Magnesium we use the same logic as for Calcium:--
"How much Magnesium should I add as a first dose?"
"Have no idea. But it must be a safe amount.".... .... ....
...
_

I hope you see how it goes. I have decided that fertilizers are the only way to get the plants growing. The answer to all problems is "Chemicals!". Just like EI and PPS. And that works but you will agree - it is not right. None of the 3 methods go into details about substrate, light, filtration... We assume you know it all or have common sense about things you have no idea about. That's lots of assumptions.

SubZero, the way I talk about it here, will:
1. Start you on the way to keeping a clean planted tank
2. Give you a guaranteed tool to fight algae if needed 
3. Help you be critical of what you do to your own tank.

All those together.

--Nikolay


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## tokyo

niko said:


> Tokyo,
> 
> And I didn't respond as if I was offended. Just stating how I came up with subZero back then.


My mistake, I misinterpreted the tone of your response.

I don't mean to be a pest, I think I am being too vague with my question. Your last response describes everything I understood from your first description. What I'm having trouble with is "why do you stop at 3g?" You say

"Is 3 grams Calcium in 55 gallons of water too much?"
"Have no idea. But I know for sure it's in the tank now. It's got to be available to the plants."

But would this not be true after you added the initial 1g? What is the reasoning for increasing it to 3g instead of leaving it at 1g or even increasing it to 5g or more?

Is it just an arbitrary number(doubtful)? Is the intention simply to continue increasing the amount over the week regardless of the actual amount increased, assuming it is kept at a safe level?

Hope I am not being a bother. I am just curious if there is any weight to the quantities or if it is simply a starting point to get the aquarist to start paying attention to their plants.


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## niko

Yes, I repeat myself. At times intentionally, but not usually not.

The starting 1 to 3 grams of Calcium is a range that I know is enough for the plants to grow. These are numbers for 55 gallons, for my water, in my tanks, and are taken from previous experience. When you are new to this hobby you do not have an idea what is "low" what is "high". Look at the original post here - look for the KH/TH and pH of my water (3-4 and 7.0-7.2). If your water is close to that you will know that my numbers will work for you too.

For my water:
Calcium: 1 gram is a little too low. 3 grams is enough to sustain a tank full of plants (about 80% full of plants!). 
Mg, NO3, P, Fe/Traces: Look at my numbers. The logic is the same.

So I start with 1 gram Calcium. The progression to 3 is just an attempt to see if something will change. And playing it safely. Without the other nutrients I don't expect any change. Note that normally until you add Phosphate the plants do not grow at all or grow very slowly. But if you add only P and nothing else the plants will not grow. So you are trying to safely get to a point where you know you have provided everything. Without any excess.

One thing to remember is that with all 3 - EI, PPS, and subZero - you may do everything exactly as they suggest but your plants will still not grow. Or you get algae. This is when the limitations of these "methods" become obvious - they do not look at the aquarium as a system. And because of that the tendency is to try to solve all problems by adding more or less fertilizers + doing water changes. All 3 "methods" assume you have common sense or know how to run a planted tank... except you don't have an idea how to fertilize. That's a pretty funny assumption, actually.

--Nikolay


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## Michael

Nikolay, would you comment on the different ways subZero and Walstad method work?

The reason for asking is that, as you know, I've had really good results with Walstad, and would recommend that method to a beginner without hesitation. Of course, I have not tried subZero, but I wonder if these two methods might both be simple, predictable ways to achieve the same result: a stable, resilient mature aquarium.


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## niko

First of all - I've done subZero only in CO2-supplied tanks. The 6 week starting period is so short because of the CO2.

From what I know about Walstad's El Natural method the substrate is truly the basis of everything happening in the tank. It provides not only nutrients but also CO2. The CO2 is not as much as in subZero (EI or PPS). 

I think that we will all agree that the higher CO2 + higher light drive the need for more nutrients. EI goes overboard with the nutrients, PPS is more careful, subZero takes the fertilization to the absolute minimum - only as much chemicals as the plants need.

So this is something that Walstad and subZero have in common - the nutrients are available only when needed. Walstad's substrate makes sure of that. SubZero does that making you, the hobbyist, work.

Walstad's approach is closer to ADA's. The substrate is a place where nutrients are stored, exchanged, transformed back and forth, and stay hidden from the water (where algae can feed on them). SubZero resembles ADA's approach because of the minute amounts of fertilizers added to the water. They get used up quickly in both cases. But ADA pays attention to many things, not just the plant health. Fertilization is done very carefully - nothing floats free in the water - and fertilization is related to light levels, CO2 levels, tank stage. EI, PPS, subZero ignore such approach, especially the role of the substrate.

Walstad does not ask you to add fertilizers to the water. SubZero does, exclusively. 
Walstad uses the rich substrate to run the tank. SubZero uses pure chemicals. This is like eating full healthy meals vs. ingesting protein powders, scooping dry starch from a box, and sipping sunflower oil. Sooner or later you are going to need to eat other things. Walstad provides them all to use when they are needed. And so does ADA.

Downside of Walstad's method - you cannot have a tank that looks fully developed in only a few weeks. EI offers you this in an insanely short time - with stems you can have a tank full of plants within 3-4 weeks if not earlier. SubZero leads you there in about 6 weeks. Such short periods of time are completely unnatural. Walstad relies on a slow and proper establishment. EI, PPS, subZero fake the proper establishment until it actually happens. Then they take credit for it. They make the process fun, enjoyable, and with a sense of control (subZero being the best providing you with a guaranteed way to control algae). All that is just what the average hobbyist wants - a quick and fun hobby, an active community discussing all sorts of things, the same issues, etc. 

--Nikolay


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## Michael

Thanks! That is a clear and fair comparison. Very importantly, each hobbyist can make an informed choice of which method is the best fit for him/her.


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## xmas_one

Niko, any thoughts on a subzero approach to co2 levels? Currently in the states it seems as if the general ideology is to blast the tank with as much co2 as the fish can take, this seems silly to me. Wouldn't it make more sense to inject just as much co2 as the plants can use? I've been trying this on a 50 gallon, I watch the pH and dial the co2 so it reaches an equilibrium where the pH will stay more or less the same with the co2 running. Prior to doing this the pH would drop considerably until the controller cut it off, and then it would bounce back up...


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## niko

When I came up with subZero I ran the CO2 as fast as I can. That is one of the dumbest things one can do. Not because of the plants but because of the organisms that comprise the biofilter. They function best at pH of 7.5 to 8.0. Running the CO2 at maximum all the time supresses the biofilter. Yet in the US we run high CO2 and don't even blink.

If you are adjusting the CO2 to a level that is enough for the plants then you are doing what ADA is doing too. Tailoring the amount of CO2 to the plant needs. They do it a little different, but the idea is the same - provide CO2 only when it's needed. They keep 99% of their tanks at pH=6.8. And not all the time - at night they pump air in the tank. That helps the biofilter a great deal but also does not give algae much chance to use up excessive CO2. It does seem that you are doing something similar, doesn't it?

In the light of how subZero works (providing just enough nutrients for the plants, and not an excess) it would be logical to extend the method to involve controlled CO2 supplementation. Which will be emulating ADA - highest CO2 in the midle of the day (or when the light is stronger) and less CO2 before and after the strong light + air at night.

By the way I recently read somewhere that in the first 2 weeks of the tank's life ADA keeps a lower temperature on their tanks. Like 2 degrees Celsius lower. Plus they do not run the CO2 at all. I don't know how practical these 2 things are but it all goes along with the idea to provide nutrients/factors ONLY when they are needed. One can expand that to any nutrient/factor - fertilizers, CO2, air, temperature, light intensity, light duration, even water changes. Now that sounds more like a real method, not like what most people do here in the US where fertilizers rule and strong light/CO2 are the norm.

--Nikolay


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## JustLikeAPill

Here is something from an ADA e-mail I got today in the Q and A section.

Q) How do you decide which soil to use for each layout? In addition, *I felt
that a large amount of CO2 was added from the initial set-up period. Doesn't it
have any negative impact?*

A) Aquatic plants grow faster on Aqua Soil Amazonia which is rich in organic
nutrients, and this is why I use this soil in most cases. With Amazonia with
its rich organic nutrients, the tank water sometimes turns slightly yellow or
cloudy depending on the condition of the filter. However, turbidity is usually
removed if the water is changed frequently and, once the biological filtration
media installed in the filter starts to function fully, I do not really worry
about such turbidity during the initial set-up stage of an aquarium. This kind
of trouble can be avoided if you can prepare a filter with a pre-activated
biological filtration medium. Now, we move on to the question of CO2 injection
volume. One of the tips to avoid any failure in the aquatic plant layout is to
plant aquatic plants as much as possible. This is because aquatic plants are a
natural filter having a high water purifying capacity. I planted Epipremnum sp.
in a 4m tank in my house, and algae seldom grows in the tank, as Epipremnum sp.
has very powerful water purifying properties and its roots spreading in the
water absorb excessive organic matter. *A lot of aquatic plants were planted in
the 90cm tank that was produced the other day, so I don't think the CO2
injection volume was too much, nor would it have any negative impact. Rather,
I very often feel your CO2 injection volume is too little.*


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## niko

I don't follow - who is saying the bold font words?

--Nikolay


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## JustLikeAPill

I made that bold because that was the pertinent part about CO2. That is from the newsletter No. 078 sent out by Aqua Design Amano CO., LTD.


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## fishyjoe24

but haven't most of us figured out that the tank needs to be 50-75% filled with plants from the start. and the filter should be 10% volume of the tank, and turn the tank over 6-10 times... / us using the liquid how do we measure all this stuff we have to look at the plants..


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## Michael

Translations from the Japanese often leave much to be desired.


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## niko

Yes this Q and A that Pill posted above is a classic example of what kind of information trickles to us after translation. Pretty hard to understand the hows and whys. Huge room for interpretation and mistakes.

In another interview Amano talks about ADA's canister filters and he does say that he considers a sump better. Because of the Oxygen.

So it appears that, logically, in a planted tank we have a predicament - the bacteria needs high pH (to filter the water efficiently) but at the same time we need CO2 (to make the plants grow) which lowers the pH. There is a happy medium I guess and once again the best example would be ADA's tanks - pH=6.8 very much in every one of them. Plus a CO2 increase/decrease connected to the intensity of the light.

My personal take on this - it is best to run the CO2 from day 1. Because we want the plants to establish roots as fast as possible. That will happen faster with CO2. I'm not sure if EI talks about actually starting a tank. I know PPS doesn't and Edward had a hard time coming up with advice about the intitial period. Whenever these "methods" talk about the initial period they do it as an afterthought. Since this is a subZero thread I got to point out that subZero is an approach that helps you with the tank development starting with day 1.

--Nikolay


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## carlschr

Wondering if there has been any more experience from those attempting to transition from a tank that doses EI and blasts CO2 to this "lean/subzero" approach? 

A quick note about our situation. I've been doing most of the setup and maintenance of our planted tank since we randomly decided to try out a high-tech planted tank after not keeping fish basically ever (except for a few goldfish and neon tetras as kids). We recently rennovated our 40 breeder that has been running fairly high lights (2x39 T5HO), CO2 till just before the fish are gasping, EI fertilizers, and inert (eco-complete) substrate for about three years. 

My wife has gotten bitten by the aquascaping bug recently, so we decided to rennovate and she's taking more of a role in maintaining our tank. She has been asking lots of questions about why we do things the way we do. This has caused me to rethink the information and methods that led me to manage our tank like this... For instance, I had been keeping the temperature at 78 degrees for no particular reason. Mary came across a chemistry website that said that lower temperature water can hold more dissolved gases than higher temperature water. We now are in the process of reducing our temperature from 78 to eventually 74, in hopes that lower temps will allow more o2 and co2 to dissolve in the water. We're thinking more oxygen would help our semi-gassed fish by providing more 02 while maintaining our Current CO2 levels. It seems that more Oxygen should be good for the beneficial bacteria too. She has also added an airstone at night, which the fish seem to like. 

I've generally had long stretches of clean and nicely growing tanks for months at a time, and then gotten lazy and had algae outbreaks (primarily BBA). The more CO2 and more flow routine was followed to minimal effect. Tearing anything affected out and starting almost all over seems to do the trick, but doesn't lead to being able to grow in a nice stablished aquascape. The just-below-death CO2 doesn't seem particularly good for the fish...

We're not growing anything too difficult: anubias, crypts, hygrohila angustifolia, hair grass, a few random easy stems and some recently planted glosso and HC. Mary is hoping to add staurogyne repens and Christmas moss to this crew. 

Our fish haven't fully adjusted to the new scape, which went from pretty dense jungle to a more open tank. They are pretty much schooling in our "valley" in the shadow of the willow hygro. If they arent hiding in the crypts. We've got a big 20+ school of rummynoses, plus black and regular neons, corys, otos, red cherry shrimps, a bristlenose pleco and a long-fin white cloud. Mary's current theory why the fish dont seem to want to go out into the open much, is that the light is too bright...which I can't really deny, because they swim all around at night when the lights are off. Especially since the recent common thinking seems to say that two t5ho's over 40 gallons is past high light, it seems worthwhile to rethink how much light we're putting into the tank.

Additionally, Mary has started turning on the C02 at a slower rate 4 hours before the lights come on so that the CO2 is at optimal levels throughout the photoperiod and so the pH swing will be more gradual for the fish. We had been starting the CO2 when the lights came on and blasting it to reach 30ppm quickly. The lights go on at 3:30pm, so we can enjoy the tank after work, but she has observed that the tank gets a fair amount of indirect sunlight between 11:00am and 1 pm and she thinks having a little CO2 in the water at that time will be good for the plants and bad for the Algae. 

Anyway..

This subzero method does seem more elegant than the "overload" approaches. Being able to have a more reasonable CO2, fertilizers, and lights has some appeal - and should be better for the fish and shrimp. 

All of which leads me back to my question....anyone succesfully switched from a maximalist to a minimalist system? I wonder if it would be best to go to zero on the fertilizers, roughly half the co2 (dark green on the drop checker?)' and then build the fertilizers up via the subzero method. Or, somehow work your way down from the current conditions until you see growth/conditions slow and then maintain a bit more than that? Seems like working from below would be better to find the minimum, but might be more of a shock to the plants/fish. How would you handle taking the lights down to a lower level? Just stick a screen over it and let everything re-adjust before dealing with the other inputs?

Thoughts?

Carl


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## niko

Carl,

First off I wrote this post to give a perspective on how water column fertilization is an inferior way to run a planted tank.

A better way is to use a substrate that provides the nutrition. That does not mean that the substrate must contain all the nutrients. There is a way to add liquid fertilizers to the water which does not lead to accumulation of the chemicals in the water. That is the best, most stable, and proven way to run a planted tank. Simply put the nutrients are available but are hidden and only the plants can get to them.

If you are interested in doing something like that you have 2 options:
1. Get AquaSoil + learn as much as you can about the ADA system
2. Follow this thread:
http://www.aquaticplantcentral.com/...iciting-input-new-way-make-mineralized-6.html

In case you do not want to switch to a substrate that will actively help your tank stay clean and be stable you can work toward using SubZero. But once again - that is not a great way to run a planted tank. You will be ignoring things that can help you a lot.

To transition to SubZero you cannot just "reset" the nutrients and try to start from a completely nutrient defficent tank. The most common mistake in the planted tank hobby is the mixing of approaches. In your case if you try to reset the concentrations of nutrients you will miserably fail. Lots of water changes and no fertilization will lead to severe defficiencies. Some plants will live some will wither and die quickly. No telling which species.

So if you still want to do something like that you must first "calm down" the tank. That means one thing - much lower light. This will go a long way toward limiting algae. Note that the CO2 must not be completely switched off. many plants do just fine with very low light and at least some CO2. But if the light is low and there is no CO2 they will die.

I'll write more later.

--Nikolay


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## Michael

Carl, this may or may not be pertinent, but in the el Natural forum there are several suggestions for adding soil-based substrate to established tanks. The discussions are dispersed and hard to find. If you are interested, i can summarize when I have more time.


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## Silvering

Michael, please do - I'm interested too! (Maybe there should be a new thread about that?)


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## Michael

I'm not sure this deserves its own thread. . .

Basically, the goal of these ideas is to get the soil into solid, conveniently sized pieces that can be inserted under the existing substrate. The most common approach is to freeze it. Wet mineralized topsoil, with its pudding like consistency, is ideal for this. Pour a thin layer of the semi-solid soil into a shallow, flat dish, or into ice cube trays. Freeze solid, then work fast to push pieces under the substrate before they melt. The frozen soil may float, so the cap has to be heavy enough to keep it submerged until it melts. Obviously, this could lower water temperature a lot.

Next method is to mix the soil with just enough clay so that the moist mixture will stick together. Form into appropriate size pieces, and dry thoroughly. This should make them hard enough to handle and push under the cap before they soak up water and become soft.

Last idea is to put the soil into soluable or bio-degradable packets. Gelatin capsules would work, but even the biggest capsules would take great patience to fill and insert. You could wrap the soil in cheese cloth or tough paper. The cloth or paper would soften and decompose over time, allowing plant roots to grow into the soil.

*Big Disclaimer:* I've never tried any of these methods! I think this is a process that would be best done gradually over days or weeks, rather than all at once. And of course, you don't need to do the entire tank.


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## jeff5614

carlschr said:


> Wondering if there has been any more experience from those attempting to transition from a tank that doses EI and blasts CO2 to this "lean/subzero" approach? ...Carl


Since you ask , I've been transitioning or I should say have transitioned my tank from a standard EI dosed tank to one with minimal water column ferts. Niko has posted a lot of info on flow, ferts, filtration, substrate etc., in regard to ADA's method of running a planted tank which really had me doing some thinking. Including that after quite a few months any substrate will become an active substrate as mulm accumulates and bacteria does its thing. My tank is a 75g with a lot of java fern, moss, a bit of blyxa japonica, S repens, dwarf lobelia, E vesuvius and a new carpet of L. mauritiana, M. minuta and E. belem that I started a couple of months ago and is steadily filling in. Before starting the transition I was using 2x54 T5HO sitting right above the tank, pumping in a lot of CO2 and dosing the standard EI amount for my size tank. I had to deal with a small amount of BBA on the driftwood every couple of weeks and some GSA on the glass.

I've been running my tank ala ADA for the past couple of months. I've been dosing water column ferts at the levels ADA recommends when using their ferts. I daily add 0.3ppm NO3, 0.1 ppm PO4, 3 ppm K2SO4, and 3 ml of Flourish Comp for micros and Fe. I do a 30-40% water change weekly.

I inject CO2 so that my pH does not drop below 6.7 to avoid inhibiting the bacterial filter which means my CO2 levels peaks around 12 ppm, which when you do the calculation on ADA tanks comes out to the same levels they use. CO2 comes on with lights and goes off with the lights. I also added a set of lily pipes and installed them as does ADA and raise them at night to aerate the tank to add O2. Flow is circular and you can see water movement throughout the tank.

I've lowered lighting to 1x54 also.

The plants are healthy and growth is steady but not overwhelming like a highlight EI tank full of stems. Algae is pretty much a non issue for me right now. I removed a small tuft of BBA from the driftwood a couple of weeks ago and it hasn't reappeared, at least not yet.

I'm happy with the tank as I can be. It's been the lowest maintenance tank I've had in a long time and it's just really been refreshing for me as far as the hobby goes.

I'm really appreciative to Niko for all the info he has provided in his posts and his challenge to get us to think outside the box a bit.

Here's a pic of my tank from about a month ago. You can see the lawn hasn't filled in yet. As I said slow but steady and healthy and thicker now than when this photo was made.


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## carlschr

Wow Jeff, your tank looks amazing! What process did you use to transition? Reduce lights first, then ferts and co2? Did you adjust in stages, or just jump to the new level? I have spent a lot of time reading Niko's dummy questions and rethinking some aspects of how I run my tank. I didn't see what substrate you're using, but it looks like regular gravel? We just rescaped with a bunch of new Eco complete, so I'm not too keen on taking all of that out and replacing with aqua soil, mts, or anything else...which leads me to...

Michael - thanks for the great ideas on putting soil into existing substrate. Has anyone out there tried this? Seems like a good half step, better than osmocote tabs for instance? Mixing in a little clay would be nice, given that I think I read that aqua soil contains clay and, being negatively charged, it sequesters other nutrients from the water column until necessary. Does "regular" mineralized soil do that too?

Niko - I understand that you didn't lay out the subzero method as a "good" way to run a tank, but just as an example of one that doesn't required the overdoses of fertilizer contained in PMDD and EI. However, an ultimately flawed method that is still reliant on continual dosing of the water column. 

However, since I've been rethinking some of the "common understanding" that I've been running the tank with, I'm thinking it might be a better way to go thank high lights and EI - given that I'm not interested in completely replacing my substrate so won't be going "full ADA." 

Would you recommend adding true soil per some of the ideas Michael laid out? Seems like building the soil buffering capacity should be a good thing across the board, and we've got deep enough substrate to get it in pretty good I bet. 

Thanks to Niko for the threads that got me re-thinking things, and Jeff and Michael for the experience and ideas. 

Carl


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## carlschr

Just for fun, here's our tank as of yesterday.










Carl


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## Michael

"Michael - thanks for the great ideas on putting soil into existing substrate. Has anyone out there tried this? Seems like a good half step, better than osmocote tabs for instance? Mixing in a little clay would be nice, given that I think I read that aqua soil contains clay and, being negatively charged, it sequesters other nutrients from the water column until necessary. Does "regular" mineralized soil do that too?"

You're welcome. The ingredients for MTS include clay for reasons you state. Mixing a soil with clay to "retrofit" a substrate would give a higher percentage of clay that normal MTS. But this might be a good thing. Clay-derived substrates have been used for a long time with good results. The list includes Fluorite, laterite, Turface, Soil Master select, cat litter, oil-dry, akadama, etc. The only type of clay one normally avoids are the colloidal clays. These have extremely tiny particles which never settle out of the water, but some people have used even these with success.


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## jeff5614

Carl,

I reduced lighting and ferts at the same time. The substrate is just regular aquarium gravel with a good amount of mulm. I have no desire to pull all the plants and fish out to redo the substrate but if I ever do I'll probably give AS a try.


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## niko

I have stuck frozen pieces of soil in the gravel under the roots of the plants. But as usual I had a good idea and stupid implementation. I did not really pay attention what soil I used. I just got some fertilizer free Miracle Grow soil, mixed it with some water (made mud) and froze it in a flat plastic dish. Broke off chunks and used tweezers to place them under the roots of plants.

The soil I used was apparently too weak. I did not see any difference really. I know why now - not all soils that are clean, natural, whatever will work for our purposes. 

Funny thing - For 3-4 weeks now I've been thinking about transitioning a full fledged EI tank that I have maintained for 6 years now to a root oriented feeding. The thing makes about 1 lb of cuttings every single week (55 gal. tank). And the algae is ever present, although in small amounts. Since the tank is full of swords and crypts mainly I really need to wake up and start root feeding. The discussion about sticking iced earth under tropical plant's roots may be a bit funny because it's ironic, but it is interesting to me too because it makes me think about actually giving it another try AND what soil to use this time.

--Nikolay


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