I found in a paper somewhere that in marine fish, nitrogen excretion occurs for 10-20% in the form of urea and 80-90% ammonium.
So, I figured I match that in my DIY nitrogen additive.
I use Randy's ammonium bicarbonate recipe and add some urea to make the nitrogen content 90% ammonium and 10% urea. Therefore, I add 0.84 grams of urea to each 20 grams of ammonium bicarbonate.
I have never used anything else than this mixture as an N-source. So I can not compare it to anything else. Nor can I say what the effect of the added urea is. Realistically I don't think it makes a difference. It just seemed logical to mimic the nitrogen excretion from fish.
So, I figured I match that in my DIY nitrogen additive.
I use Randy's ammonium bicarbonate recipe and add some urea to make the nitrogen content 90% ammonium and 10% urea. Therefore, I add 0.84 grams of urea to each 20 grams of ammonium bicarbonate.
I have never used anything else than this mixture as an N-source. So I can not compare it to anything else. Nor can I say what the effect of the added urea is. Realistically I don't think it makes a difference. It just seemed logical to mimic the nitrogen excretion from fish.