DIY Ammonia dosing for low nitrate systems

[jmon22]

78 pages later. Any consensus between dosing ammonia and nitrates? My nitrate keeps bottoming out. Been dosing stump remover (which caused phosphates to bottom out). Dose both now and am able to get everything in the right ballpark now but would like to get more sophisticated about it.

 

[Red_Beard]

78 pages later. Any consensus between dosing ammonia and nitrates? My nitrate keeps bottoming out. Been dosing stump remover (which caused phosphates to bottom out). Dose both now and am able to get everything in the right ballpark now but would like to get more sophisticated about it.

My take has been use straight ammonium for maintaining no3 demand. Either dose nitrate directly to get your target value and use ammonium to maintain, OR mix some urea at a rate of 5grams urea to 20grams ammonium per 1 liter of RO water.

 

[Randy Holmes-Farley Verified Community Expert]

78 pages later. Any consensus between dosing ammonia and nitrates? My nitrate keeps bottoming out. Been dosing stump remover (which caused phosphates to bottom out). Dose both now and am able to get everything in the right ballpark now but would like to get more sophisticated about it.

I do not recommend stump remover under any circumstance. Too much potassium and no purity assurance.

 

[jmon22]

I do not recommend stump remover under any circumstance. Too much potassium and no purity assurance.

Yeah I'm moving away, but not sure to what. Sodium/Calcium Nitrate or Ammonia?

 

[Randy Holmes-Farley Verified Community Expert]

Yeah I'm moving away, but not sure to what. Sodium/Calcium Nitrate or Ammonia?

I dose ammonium bicarbonate to my system. All of those are ok choices.

 

[ShanePike]

78 pages later. Any consensus between dosing ammonia and nitrates? My nitrate keeps bottoming out. Been dosing stump remover (which caused phosphates to bottom out). Dose both now and am able to get everything in the right ballpark now but would like to get more sophisticated about it.

Here's a quote from the first post in this thread: "it is safe to add 0.1 ppm ammonia (equivalent to 0.36 ppm nitrate) at once to any reef tank". I was dosing ammonia for weeks before realizing that I was going to have to dose at least 30x more to get to where I wanted to be. That felt like a very dangerous amount of ammonia.

So, I switched to dosing a homemade NeoNitrate replacement on RHF's advice. I used food-grade sodium nitrate from Amazon. It has been way easier to get nitrates up and keep them up.

 

[Randy Holmes-Farley Verified Community Expert]

Here's a quote from the first post in this thread: "it is safe to add 0.1 ppm ammonia (equivalent to 0.36 ppm nitrate) at once to any reef tank". I was dosing ammonia for weeks before realizing that I was going to have to dose at least 30x more to get to where I wanted to be. That felt like a very dangerous amount of ammonia.

So, I switched to dosing a homemade NeoNitrate replacement on RHF's advice. I used food-grade sodium nitrate from Amazon. It has been way easier to get nitrates up and keep them up.

It’s not any more dangerous than adding more fish to add the same ammonia.

 

[karakurt]

I dose ammonium bicarbonate to my system. All of those are ok choices.

Could you please tell me if I can use (NH₄)₂CO₃ instead of NH₄HCO₃?
Will it cause any harm?

 

[Randy Holmes-Farley Verified Community Expert]

Could you please tell me if I can use (NH₄)₂CO₃ instead of NH₄HCO₃?
Will it cause any harm?

It is fine to use, but it will smell more/evaporate ammonia faster.

Ammonia plus one molar equivalent of CO2 gives ammonium bicarbonate.

Ammonia plus one half equivalent of CO2 gives ammonium carbonate.

 

[iprayforwaves]

It is fine to use, but it will smell more/evaporate ammonia faster.

Ammonia plus one molar equivalent of CO2 gives ammonium bicarbonate.

Ammonia plus one half equivalent of CO2 gives ammonium carbonate.

Would you mix up the solution the same?

 

[Randy Holmes-Farley Verified Community Expert]

Would you mix up the solution the same?

Not sure what you mean. The weight to add to each the same ammonia potency is not the same.

 

[iprayforwaves]

Not sure what you mean. The weight to add to each the same ammonia potency is not the same.

What weight of ammonium carbonate would give the same potency as the bicarbonate recipe?

I have the carbonate version available locally.

 

[BriDroid]

What weight of ammonium carbonate would give the same potency as the bicarbonate recipe?

I have the carbonate version available locally.

Not to speak for Randy, but I'm pretty sure he has said in the past that they are close enough that it won't matter. Most of us use the planted tank site calculator, and it doesn't even list either of them, it uses ammonium nitrate, and he said that is close enough

 

[EnterName]

What weight of ammonium carbonate would give the same potency as the bicarbonate recipe?

I have the carbonate version available locally.

13g (Ammonium carbonate anhydrate) or 15g (ammonium carbonate monohydrate) will give you the same ammonium amount than 20g ammonium bicarbonate.

Maths/Chemistry:
20g ammonium bicarbonate (original recipe posted by Randy) is roughly 20g / 79.06g/mol ≈ 0.26mol NH₄HCO₃.
Ammonium carbonate has 2 NH₄ molecules while ammonium bicarbonate only has 1, which means you only need half as many molecules of it (0.26mol/2 = 0.13mol). Together with the molar masses of the reagents we can calculate how much you will need to create an equally concentrated stock solution:

0.13mol · 96.09g/mol (NH₄)₂CO₃ ≈ 13g (NH₄)₂CO₃
0.13mol · 114.10g/mol (NH₄)₂CO₃ · H₂O ≈ 15g (NH₄)₂CO₃ · H₂O

 

[Randy Holmes-Farley Verified Community Expert]

Thanks for the calculations. :)

 

[TheDuude]

Anyone notice a die off of macroalgae? Corals seems to be responding well. Nitrates up to 10 from 0 dosing Am bicarb. My chaeto has turned much darker green and is not growing. Previously would harvest half of a bucket(5g) monthly. Phosphates high around .8

 

[Evensong]

I have:

1. Very low nitrates (basically undetectable on my Red Sea test)
2. High phosphates (0.35 according to Hanna Checker ULR test)
3. Very low bioload (4 mollies, a clown, and a few frags so far in a 200 gallon system)
4. Some macro and plants (ulva and mangroves, plus some GHA that I allow to grow in the sump bc the mollies love it). No algae, cyano, or other issues.
5. A bunch of leftover Dr. Tim's ammonium chloride from when I cycled the tank.

I know the long term is to add more bioload to boost the nitrates, but in the meantime is there any reason I couldn't dose the Dr. Tim's I have sitting around to boost the nitrates and feed the macro? According to their dosing guide, 30 mL would be the equivalent of 2ppm (for 150 gallons of water after accounting for rock, substrate, etc). To dose the 0.1ppm rate recommended here, that's 1.5 mL once or more per day.

 

[EnterName]

I have:

1. Very low nitrates (basically undetectable on my Red Sea test)
2. High phosphates (0.35 according to Hanna Checker ULR test)
3. Very low bioload (4 mollies, a clown, and a few frags so far in a 200 gallon system)
4. Some macro and plants (ulva and mangroves, plus some GHA that I allow to grow in the sump bc the mollies love it). No algae, cyano, or other issues.
5. A bunch of leftover Dr. Tim's ammonium chloride from when I cycled the tank.

I know the long term is to add more bioload to boost the nitrates, but in the meantime is there any reason I couldn't dose the Dr. Tim's I have sitting around to boost the nitrates and feed the macro? According to their dosing guide, 30 mL would be the equivalent of 2ppm (for 150 gallons of water after accounting for rock, substrate, etc). To dose the 0.1ppm rate recommended here, that's 1.5 mL once or more per day.

I could imagine your phosphates aren't assimilated due to a nitrogen (and/or carbon) limitation. So once you add ammonia, phosphates might finally come down. (Had a similar experience once, but of course it is hard to prove that this is the actual underlying cause for the sudden phosphate reduction)

You should be able to use Dr. Tim's ammonia solution as it is based on ammonium chloride, as far as I know.

Edit: Randy has a fair point about purity down below.

 

[Randy Holmes-Farley Verified Community Expert]

I have:

1. Very low nitrates (basically undetectable on my Red Sea test)
2. High phosphates (0.35 according to Hanna Checker ULR test)
3. Very low bioload (4 mollies, a clown, and a few frags so far in a 200 gallon system)
4. Some macro and plants (ulva and mangroves, plus some GHA that I allow to grow in the sump bc the mollies love it). No algae, cyano, or other issues.
5. A bunch of leftover Dr. Tim's ammonium chloride from when I cycled the tank.

I know the long term is to add more bioload to boost the nitrates, but in the meantime is there any reason I couldn't dose the Dr. Tim's I have sitting around to boost the nitrates and feed the macro? According to their dosing guide, 30 mL would be the equivalent of 2ppm (for 150 gallons of water after accounting for rock, substrate, etc). To dose the 0.1ppm rate recommended here, that's 1.5 mL once or more per day.

I’m not certain if Dr Tim’s is adequately pure for routine dosing since that is not the intended use, but it may be fine.

 

[rishma]

I have:

1. Very low nitrates (basically undetectable on my Red Sea test)
2. High phosphates (0.35 according to Hanna Checker ULR test)
3. Very low bioload (4 mollies, a clown, and a few frags so far in a 200 gallon system)
4. Some macro and plants (ulva and mangroves, plus some GHA that I allow to grow in the sump bc the mollies love it). No algae, cyano, or other issues.
5. A bunch of leftover Dr. Tim's ammonium chloride from when I cycled the tank.

I know the long term is to add more bioload to boost the nitrates, but in the meantime is there any reason I couldn't dose the Dr. Tim's I have sitting around to boost the nitrates and feed the macro? According to their dosing guide, 30 mL would be the equivalent of 2ppm (for 150 gallons of water after accounting for rock, substrate, etc). To dose the 0.1ppm rate recommended here, that's 1.5 mL once or more per day.

Probably fine but will reduce alkalinity so you’ll want to account for that.

I think I bought my ammonium carbonate lifetime supply for $9 so it’s not a huge investment. I would bet your phosphate declines when you start dosing ammonia.