# Would like to understand fundamentals better



## rpadgett37 (May 23, 2014)

I have plans to setup an NPT, but before I do, there are some things I would like to understand better.

First is the cap for the soil. I have seen mixed opinions on what is the right thing to use and why. For myself, I decided to use SC Flourite Black due to the small grain size. If I understand it correctly, it is very good at bonding with plant nutrients, storing them for plant use. If that's right, will those nutrients in the cap be available to the plants themselves?

Second, where do the nutrients in the water for water column feeders come from? (Fe, Mg, Ca and K plus trace minerals and anything else I am missing)

What stimulates nitrification in the soil? In the initial setup, how is the ammonia getting removed from the water such that keeping fish in the tank right away is safe?

What are the most important type of plants to have in the NPT (meaning root feeders and water column feeders, whether floating or planted)? I would like to understand better here what functions each type serve, as mentioned above, how they derive their nutrients and how they function together to provide a stable enough environment for immediate stocking.

That about covers it for now. I'm sure more questions will follow.


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## Michael (Jul 20, 2010)

Hi, see my comments in *bold* below.



rpadgett37 said:


> First is the cap for the soil. I have seen mixed opinions on what is the right thing to use and why. For myself, I decided to use SC Flourite Black due to the small grain size. If I understand it correctly, it is very good at bonding with plant nutrients, storing them for plant use. If that's right, will those nutrients in the cap be available to the plants themselves?
> 
> *The main purpose of the cap is mechanical; to hold the soil in place and give the plants a firm substrate for their roots. Your Flourite will be fine, and has the added advantage of having the ability to absorb nutrients out of the water and hold them for plant roots. (This is called high cation exchange capacity CEC.) The plant roots can break the chemical bond between Flourite and nutrients as they need to.*
> 
> ...


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## Tugg (Jul 28, 2013)

Seachem's Flourite Black is a clay based product; as such, it has a property called CEC (cation exchange capacity). This causes positive ions (Al,H,Ca,Mg,K,NH4,Na) to statically cling to the material. By doing so, it pulls it from the water and holds it where plant roots can take it up, but algae can't use it. This would mean that in addition to the HIGH CEC of the soil, even the cap would feed your plants. On the flip side, something like Black Diamond Blasting sand, or pool filter sand would only serve as an anchor to hold plants down, as well as prevent the soil from clouding the water.

Tap water has dissolved nutrients to begin with. In addition, the food you feed fish gets broken down and provides these nutrients as well. An El Natural tank is typically fertilized by feeding.

Nitrification bacteria are present everywhere. The process of cycling a tank is to simply allow them the time to grow a large enough colony to support the fish. In a heavily planted tank this cycle may happen silently though. The plants can potentially take up all the ammonia faster than the bacteria can process is.

All types are important and server a role. The heavy root feeders (swords, crypts) help pump O2 into the substrate and prevent it from going anaerobic/toxic. The column feeders (most stem plants) help keep the water clean, and typically have a fast growing rate (eat more waist). The floating plants are insane water cleaners. Since they are above the water, they have full exposure to the lights, and unlimited amounts of CO2. There is nothing to limit their rate of growth other than a shortage of nutrients. Not to mention, most fish like the shade and to play in the hanging roots.

As for the immediate stocking.... I'm going to be a hypocrite and advise against that. Different soils react differently when submerged. Not to mention the Fluorite is going to play with the levels in the water a little as it settles in. If the soil is nutrient rich, you may get an ammonia spike that the plants can't handle. If you do decide to stock immediately, please make sure you mineralize the soil first.


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## Tugg (Jul 28, 2013)

Well darn, If I had just waited a half hour I could have just done a quick "Yup, what he said."


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## Michael (Jul 20, 2010)

Ha! Great minds and all that. . .

Tugg makes a good point about putting fish in the tank right away. You should do this only if your soil is well prepared or you know it well enough to be sure it won't cause an ammonia spike. It is safer for a beginner to wait and test the water to be sure it is safe before you add fish.


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## SBS (Feb 26, 2013)

Yup, what Michael and Tugg said 

And I can vouch for waiting to put critters in it. I did one un-mineralized soil tank. I tested it with two Malaysian trumpet snails, one died, didn't even try to burry itself inside the substrate so I knew it wasn't safe..... and that's using a filter in that was cycled for years but I guess it got an overload plus possibly chemicals leaching.....but a month later I put a bunch of tiny baby shrimp and they were all fine. The plants had grown nuts by then and I had done a few good water changes too during that month.


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## rpadgett37 (May 23, 2014)

I was iffy about adding fish right away knowing of the volatility of the submerged soil in the first 6 weeks (give or take). I figured there was something I was missing, so the advice here makes total sense.

Got it on the rest of the points, so thanks very much for the clarification.

Regarding the water, though, I don't think my tap water will be suitable. The dk and dh both start at 1 and the PH at 7.9. In my test bottle, the ph dropped to 6.6 in 24 hours and I have to boost KH and GH to put minerals into the water and buffer the PH. It also starts with 0 Fe which proved problematic in my non-npt tanks, requiring dosing for it and trace minerals.

So given that, why not remineralized RO water? What can I do to make my tap more suitable if that is more desirable in this type of tank?

And how important is partial sunlight during the day for this type of tank? Where my room is, there isn't anything but ambient light that reaches the tanks.


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## Michael (Jul 20, 2010)

I suggest that you re-mineralize your tap water. No sense in paying for RO water when you almost have it coming out of the faucet. Adding minerals to your tap water will help to stabilize the pH.

Natural sunlight is nice if you can easily control the amount, but is not necessary. You can supply all the necessary light artificially.


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## SBS (Feb 26, 2013)

Are you going to put dolomite under the substrate? This would help holding the kh and gh in your soft water but in my case it didn't raise them, maybe I put too little. The kh gets down over time in any tank and can pull the ph down so remineralizing your tap water is best.
As far as iron goes, I have a problem with the lack of it in all my non-NPT tanks but I don't have any iron issues in the soil tanks. I have also a small bit of red clay mixed in with the soil which I suppose helps with iron levels but one needs to be careful in soft water as it can get toxic to plants apparently but that's what I've read mostly, not from experience as I have hard water.


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## rpadgett37 (May 23, 2014)

I am only planning to use Miracle Grow Organic Potting Soil and flourite for the cap. I get mixed messages about whether it by itself is sufficient for the aquarium's needs, so I don't really know if I should add anything, or what that should be. Diane's book says it is fine by itself, but others swear by adding various things, clay, dolomite, oyster shells, etc...

The hardest part I am having trouble wrapping my mind around is the nutrients for the floating plants and the fish. I understand how that works for the plants rooted in the substrate. I know there's some kind of dynamic interaction going on that provides each what they need. I'd like to know better how that works. Under ideal circumstance, I shouldn't have to dose at all. I'd just like to know better how the interactions going on in the tank make that possible and what I need to do to set it up for success all the way through.

I appreciate all the info. Very helpful in clarifying some things for me.


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## rpadgett37 (May 23, 2014)

Ok... re-read what was said above which answers my questions. Just not in enough detail that I would like  Just the same, I'll offer my understanding of what this all means. Feel to correct me if I miss or misinterpret or fill me in on what I have missed.

1. The rooted plants will derive their nutrients from the soil as well as any K, Mg, Ca, Fe that binds with the Flourite (will that precipitate the majority of these elements from the water rendering them unavailable to the water column feeders?

2. Trace minerals for the plants will come from fertilizing the soil with food which in turn replenishes nutrients to the soil for the rooted plants.

3. Some nutrients will be released into the water by the soil which serve to feed water column feeders, as well as providing minerals for fish and floating plant use (what and how I am not clear on).

4. Fish derive their trace minerals from their food and minerals in the tap water (or in my case, partial reconstitution of my tap water). They in turn return some nutrients into the water (precisely what beyond NH3 / NH4 I am unlcear about) for water column feeders.

5. Tap water, containing some minerals, also serves to feed water column feeders and for fish use (is that right?)

6. Additives mixed in with the water can assist with release of these some of these elements and trace minerals into the water (as mentioned clay for iron, I presume oyster shells for minerals. Are they necessary, meaning if I add clay, will Fe released into the water become toxic? Can the soil by itself release all that is needed? Will it precipitate into the flourite, not making into the tank?

As for adding minerals and bicarbonates to the tap, I have SC Equilibrium which adds K, Mg, Ca and Fe to the water. I use a product from Saltyshrimp called KH +. I dose SC Trace in my other tanks. Beyond that I have nothing else for trace elements. Will that Trace be needed at all?


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## Michael (Jul 20, 2010)

The one thing you seem to misunderstand is that the soil itself also has high CEC, which means that it can also sequester nutrients until plant roots absorb them.

Your biggest challenge seems to come from your soft tap water. So I suggest that you add micronutrient sources to your soil, as described in the thread on mineralized topsoil. These would be oyster shell or dolomite for calcium, red potter's clay for iron, potash or potassium chloride for potassium, etc. The Flourite also has iron. The nutrient-rich soil will release all the nutrients you need into the water when tank is new. As the soil stabilizes and releases fewer nutrients, the fish food and fish waste take up the slack. After an extended period of time (at least 6 months, maybe years), the tank MIGHT develop specific nutrient deficiencies. These will show up as symptoms on the plants, and can be diagnosed and corrected at that time.

Looking at the tank as a whole system, the Walstad method maintains a very lean water column and a nutrient rich substrate. This is the same thing Amano does in the ADA system. Chemical analysis of fish food shows that it contains all the nutrients necessary for plant growth. Fish food is the primary nutrient input to a Walstad tank. Most of the nutrients appear in form of fish waste (visible feces and invisible ammonia and other substances excreted through the gills). Some of the nutrients come from uneaten fish food, or excess food and dead plant matter that is consumed by detritivores (think snails) and microorganisms. 

Honestly, I think that if you prepare the soil well, paying extra attention to micronutrient sources, you will not need to add anything to the tap water for a very long time. Maybe never! Remember, the source of water for all natural freshwater habitats is rain--very soft and slightly acidic from dissolved CO2, just like your tap water after it is exposed to air for a while. The water chemistry changes as rain flows over natural substrates: soil and stone. You will mimic this process in your tank.


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## rpadgett37 (May 23, 2014)

I'm getting a much clearer picture. Sounding far less intimidating and much more simple than I had thought. The rain water analogy makes perfect sense.

I think I understand it well enough now to give it a go. Will re-read the soil mineralzing thread for more details. Appreciate the continuing guidance.


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