# [Wet Thumb Forum]-Advice on fertilisation regime



## Chee Boon Yong (Jul 28, 2004)

Hi,

Been doing plenty of reading here about fertilisation but still need some specific advice on my own tank. Would appreciate if anyone could provide some feedback.

Background:
4x2x2 ft tank.
6x55W PL - 330W total
CO2 - 25-30 ppm (est)
Bioload of ~150-180 cardinal tetras equivalent
NO3 - unknown (due to unreliable test kit. It shows 12.5 ppm range almost all the time)
PO4 - unknown (again poor test kit. Always showing nil)
kH maintain at 4-5
Gh unknown
Substrate is ADA soil. No base fert, except for local root tabs at crypt area.

Been reading on Tom Barr's estimative method but I've been having problems trying to grow crypts with weekly water changes. They just keep melting and the new growth is not fast enough to catch up with the melting. 

So I'm thinking of switching to the following regime: 30-40% water change every fortnight. Hopefully more stability for the crypts to grow well.

The fertilisers I have are:
Potassium suplphate (K source)
Potassium nitrate (NO3 source)
Potassium phosphate (PO4 source)
Tropica Master Grow TMG (micro, mainly for Fe)
Magnesium sulphate (not using now)
Calcium sulphate (not using now)

No idea what my tap water is. I live in Singapore and the local parameter guidance is <0.5 - 15 ppm NO3; <0.1 ppm PO4. Most local people say it is mostly low in NO3 and PO4.

Ok, my problem is that I have no idea what my NO3 and PO4 is without a reliable test kit, which I unfortunately do not have access to. My current test kit for NO3 (Tetra brand) can detect VERY high NO3 levels when I test it against a test solution (own crude brew). So at least I know that my NO3 should be below 30 ppm because it doesn't show the high range when I test my tank water. Suspect it's probably lower. The PO4 test kit (Sera brand) also can test high PO4 but cannot accurately gauge the exact PO4 level.

So my current idea is to overdose slightly rather than risk running out of any nutrients.
Week 1:
Add 1/2 teaspoon Potassium Nitrate
Add 1/3 teaspoon Potassium Phosphate
Add 1 teaspoon Potassium Sulphate
Week 2:
Repeat above dosage.
Week 3:
Water change, then repeat above dosage. Repeat entire cycle every 2 weeks.
Daily: 3-5 ml of TMG for iron.

Considering my bioload, I suspect my tank should have a reasonable amount of NO3 at any one time, hence only 1/2 teaspoon of NO3 every week. However, I'm concerned about my high light, high CO2 condition. Should I up my NO3 slightly just to be safe?

Is my PO4 dosage too high?

Should I add TMG daily or can I get away with weekly dosage instead?

My plants (other than crypts) are growing very well. But I'm dosing a little bit of everything everyday just to make sure they don't run out of anything. But it is simply not feasible for me to keep up with this daily regime. There may be times when I need to travel out of country, hence my desire to switch. Currently no visible algae except for Green Water. But my ammonia is now under control and it should go away for good once I borrow an UV light.

Any feedback is greatly appreciated.


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## Chee Boon Yong (Jul 28, 2004)

Hi,

Been doing plenty of reading here about fertilisation but still need some specific advice on my own tank. Would appreciate if anyone could provide some feedback.

Background:
4x2x2 ft tank.
6x55W PL - 330W total
CO2 - 25-30 ppm (est)
Bioload of ~150-180 cardinal tetras equivalent
NO3 - unknown (due to unreliable test kit. It shows 12.5 ppm range almost all the time)
PO4 - unknown (again poor test kit. Always showing nil)
kH maintain at 4-5
Gh unknown
Substrate is ADA soil. No base fert, except for local root tabs at crypt area.

Been reading on Tom Barr's estimative method but I've been having problems trying to grow crypts with weekly water changes. They just keep melting and the new growth is not fast enough to catch up with the melting. 

So I'm thinking of switching to the following regime: 30-40% water change every fortnight. Hopefully more stability for the crypts to grow well.

The fertilisers I have are:
Potassium suplphate (K source)
Potassium nitrate (NO3 source)
Potassium phosphate (PO4 source)
Tropica Master Grow TMG (micro, mainly for Fe)
Magnesium sulphate (not using now)
Calcium sulphate (not using now)

No idea what my tap water is. I live in Singapore and the local parameter guidance is <0.5 - 15 ppm NO3; <0.1 ppm PO4. Most local people say it is mostly low in NO3 and PO4.

Ok, my problem is that I have no idea what my NO3 and PO4 is without a reliable test kit, which I unfortunately do not have access to. My current test kit for NO3 (Tetra brand) can detect VERY high NO3 levels when I test it against a test solution (own crude brew). So at least I know that my NO3 should be below 30 ppm because it doesn't show the high range when I test my tank water. Suspect it's probably lower. The PO4 test kit (Sera brand) also can test high PO4 but cannot accurately gauge the exact PO4 level.

So my current idea is to overdose slightly rather than risk running out of any nutrients.
Week 1:
Add 1/2 teaspoon Potassium Nitrate
Add 1/3 teaspoon Potassium Phosphate
Add 1 teaspoon Potassium Sulphate
Week 2:
Repeat above dosage.
Week 3:
Water change, then repeat above dosage. Repeat entire cycle every 2 weeks.
Daily: 3-5 ml of TMG for iron.

Considering my bioload, I suspect my tank should have a reasonable amount of NO3 at any one time, hence only 1/2 teaspoon of NO3 every week. However, I'm concerned about my high light, high CO2 condition. Should I up my NO3 slightly just to be safe?

Is my PO4 dosage too high?

Should I add TMG daily or can I get away with weekly dosage instead?

My plants (other than crypts) are growing very well. But I'm dosing a little bit of everything everyday just to make sure they don't run out of anything. But it is simply not feasible for me to keep up with this daily regime. There may be times when I need to travel out of country, hence my desire to switch. Currently no visible algae except for Green Water. But my ammonia is now under control and it should go away for good once I borrow an UV light.

Any feedback is greatly appreciated.


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## nino (Oct 2, 2004)

It's hard to dose correctly if you can't test the levels. But you're dosing waayy too much phosphate. Your green water is more likely caused by the high phosphate level. Stop dosing it totally for now. I think it builds up to a high level right now. Do a large water change and don't dose anything until the green water is under control (not even iron).

After that, you can up the nitrate dosing. A lot of fish doesn't mean enough nitrate. One of my densely planted tank is overstocked and the nitrate always bottoms out every 2 days. I dose nitrate twice a week at 5 ppm each time. I only dose phophate up to 0.5ppm. 

Some crypts are very sensitive towards any changes. Just leave them alone and don't move them around. They will recover eventually. You could use root tablets under those crypts to boost their growth.

Do you use Chuck's nutrient calculator ?


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## goh (Jul 9, 2004)

Hi Boon Yong,
I am also from Singapore. Have tested NO3 and PO4 in tap water and they are undetectable, so close to none.


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## Bert H (Mar 2, 2004)

Boon Yong,
Weekly 50% water changes should not cause your crypts to melt. I have followed that regine for 2 years and the only meltdown I've had (knock on wood) was when I changed my dosing routine. I have wendtii which are supposedly one of the 'quicker melters'. The thing with crypts is to stay doing the same thing you're doing. They don't like changes, but they will be ok once you establish a routine you follow.

I agree with ninob, you're adding too much po4. I would suggest adding no3 twice a week. Some people add it every other day, but without some kind of testing, I would be cautious going that route.

HTH.


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## Chee Boon Yong (Jul 28, 2004)

Thanks everyone for replying. Thanks to Goh for pointing out SG tapwater is basically "lifeless"...







Guess my NO3 test kit is pretty junk...

For the crypts, I no longer shift them about in the tank. They've been in their present location for close to 3 months, but always when 1 new leaf sprouts, another old one melts. No more than 3-4 leaves at any one time. I'm not quite sure exactly what else I'm supposed to maintain "stably". 2 things I can think of: WC and fertilisation regime. Hence, just want to stabilise these 2 things.

Checked Chuck's calculator and revised my calculations:

With 300 ml of tapwater, I'll mix it with:
3 teaspoon of Potassium Nitrate
1/3 teaspoon of Potassium Phosphate
2 tablespoon of Potassium Suplphate.

Every week, I'll dose 100ml of this solution to give me per week:
9 ppm NO3
1 ppm PO4
19 ppm K (total from Potassium Nitrate & Potassium Suplphate)

Do a 30-40% water change every fortnight. Not just for the crypt reason, but also more for time reasons.

Main fear is running out of NO3 during the week. I figured that assuming 2ppm consumed per day, all 9 ppm (plus fish food source) should be consumed within 5 days, so maybe will run a little low on the 6th day, before dosing again on the 7th day. But I guess there's some margin for error anyway. More worried if my tank consumes much more than 2 ppm per day. What is the key observation that should prompt me to add more NO3, just in case? Reduced photosynthetic activity (less bubbles)? I had a discussion with someone else who pointed out to me that N is not necessary for photosynthesis

12H2O + 6CO2 + light → C6H12O6 (glucose) + 6O2 + 6H2O

Hence, would I be able to observe N deficiency from just "less bubbling"? Or should I observe slower plant growth as a more important indicator?


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## Roger Miller (Jun 19, 2004)

The formula you have for photosynthesis does not reflect the real complexities. Nitrogen is a major part of many of the compounds that make photosynthesis work. Even so, "less bubbling" isn't a primary feature of nitrogen shortage. "Less bubbling" can also be caused by a lot of other factors.

The major symptoms of nitrogen shortage are that older leaves die back and new growth is light colored. Your crypts may be losing their older leaves because of a nitrogen deficiency. When you observe something that looks like a nitrogen shortage then you should test to see if nitrates are present before you conclude that nitrogen is the problem. The same symptoms can be caused by other shortages or by combinations of other shortages.


Roger Miller


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## Chee Boon Yong (Jul 28, 2004)

I've started on my first course of 100ml dosing on last Saturday.

The new leaves on my rotala macrandra appears to be patchy-coloured, showing white spots. I believe that _could _be N deficiency. I intend to just continue observing and if the spotted leaves continues, I think I'll up my N.


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## Avalon (Mar 7, 2005)

First of all, invest in a better nitrate and phosphate test kit. I use an Aquarium Pharm Nitrate test kit and a Hagen Phosphate test kit. While neither are all that accurate, they provide me with a close figure that suits my needs.

Here's how I would modify your dosing schedule. Of course, this is a general routine as I have a tank very similar in spec to yours, and you will surely need to tweak it to suit your enviornment.

TMG - 20mL 3x per week (you may need to increase this depending on your plant growth and total plant mass)

KNO3 - Use Chuck Gadd's calculator to figure out what a 3-5ppm dosing would be for your tank, about 3x weekly.

KP04(?-->your phospate) - Once again check out Mr. Gadds site, but dose .5-1ppm twice weekly.

Stop dosing potassium (K) completely. You should have more than enough. This may be the reason for the white spots on your rotalla.

You should keep an eye out for Magnesium and Calcium deficiencies. After getting your nutrient levels in proper spec, upping the CO2 may help as well, but try this last.

What kind of root tabs are you using for your crypts? If they are Jobes or Miracle Grow, then this is more than likely the cause for your green water.


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## Chee Boon Yong (Jul 28, 2004)

I've been thinking of investing but it's kind of hard to find them in Singapore.

However, I'll be travelling to the US from 22 Aug onwards (for a week). Will be staying in some Illinois suburb hotel. Area is called Mundelein, if that rings a bell with anyone. So, is there some way I can get Hach/Lamotte to send to my hotel? How much should I expect to pay (excl shipping)?

Surprised I need to add so much TMG. Will give it a try.

K issue: too much K blocking uptake of calcium/magnesium? I will get a GH kit to test first. My fellow hobbyists tell me there's probably more than enough calcium/magnesium in our tap waters here. It's better to reduce K than to up calcium/magnesium, is that true?

My root tabs are some Taiwan brand, called OCEAN-FREE ROOT MONSTER. Doubt you guys in US will have heard of it. It's meant for aquariums specifically though. Doubt it's the source of my GW. Anyway, I've cleared up the GW by borrowing a UV light. Will see if the GW comes back in due time.


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## nino (Oct 2, 2004)

Yes, agree with Avalon. You don't have to dose too much K. If you're worried of lacking it, just dose 5 ppm every water change only. I believe TMG contains K also. Only dose TMG as much as you need. I wouldn't dose any until GW is gone.

GW can be caused by many things. I have similar problem right now in my new tank. It was clearing up until I moved around some plants and added more. I guess I stirred up the nutrients from my Flourish Tabs. Well, now back to pea soup again


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## Chee Boon Yong (Jul 28, 2004)

I'm now looking at the Hach website on ordering the NO3/PO4 test kits.

Kinda confused by the choices availableHach Single-parameter test kits catalog. Can anyone advise which is the correct test kit?


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## Chee Boon Yong (Jul 28, 2004)

Previous thread

Answered my own question using the search function. Sorry for wasting everyone's time.

To Roger: Why do you use the 0-10 mg/l kit? NO3 maintained at <10 ppm? Or is this measuring N, not NO3?


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## Roger Miller (Jun 19, 2004)

> quote:
> 
> Why do you use the 0-10 mg/l kit? NO3 maintained at <10 ppm? Or is this measuring N, not NO3?


As you guessed, it measures N, not NO3.

Roger Miller


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