Attn: Carbon dosing experts

[hkgar]

My tank is 180 and 40 gallon sump with total water volume about 165. Ny Ntrates are 10 and PO4 is .04 last test. Previous test was 5 Nitrate and .12 PO4. I started GFO then.

I am dosing a vinegar/vodka with a 7 to 3 ratio Currently up to 30ml/day (just increased from 25.

question is:
I seem to remember reading that there is some sort of ratio for NO3 an PO4 for carbon dosing to be effective. I can't remember , but seem to recall that if PO4 was too low dosing wouldn't limit how low NO3 could go, or maybe just the opposite, or something else entirely.

 

[Potatohead]

16:1 is ideal

 

[bertoni]

Organisms consume much less phosphate than fixed nitrogen, but the ratio varies depending on the species. A lot of people quote the Redfield ratio, which is 16:1, but it applies to phytoplankton. The organisms in your tank might vary from that ratio, but I wouldn't worry about it much. If the tank has phosphate when the nitrate is gone, a bit of GFO will fix the problem. If there's still too much nitrate, then a denitrator might be a good approach.

 

[C.Eymann]

Agree with bertoni, corals have different chemical compositions than phytoplankton. Therefore, will have a different N/P ratio and consumption. Like bertoni also said it can vary organism to organism or species to species. While the molar elemental ratio 16:1 concerning N/P is a good place to start, it might not exactly be "ideal" or super accurate for the all the different variates of life we keep in our tank, but it works. Until more research is done on this subject the 16:1 ratio seems to be the benchmark and many report good success using that guideline.