Question about NO3 in non-Co2 tank


Guru Class Expert
Jan 6, 2006
In the non-co2 article, it's said:
We can add KNO3 and KH2PO4 and show that in a non CO2 tank, excess PO4, NO3 (and Fe) do not cause algae blooms.

It's great to know and i'll confirme, it work. my question is more about the fish in the tank. What happen whit them in those estimate system?
I have a non-Co2 tank that have built realy high No3 level (between 30 and 50) and beacause I dont test, It took few weak before I realised about it.


Lifetime Charter Member
Lifetime Member
Jan 24, 2005
Re: Question about NO3 in non-Co2 tank

In my experience that won't hurt the fish.


Tom Barr

Staff member
Jan 23, 2005
Re: Question about NO3 in non-Co2 tank

EI is not applied to non CO2 tanks or tanks that get no water changes or only smaller ones/

You only add a tad of KNO3, PO4 etc to stave off deficency, you should run things on the more conservative side here, re read the article, I state this and folks can not dose as much with more fish, should let the tank drop down if you have been dosing often, that way it can be puraged via plant uptake and allow the ppm's to drop.

The deficiencies are mild in non CO2 tanks, visually, most folks can catch things without too much issue. So you can run it down leaner and add more traces, PO4 to reduce the NO3 if you want, or not add anything at all for a 2-3 week peroid.

Note plant health, growth etc and if you see a decline, dose a little and note the change.

Problems are milder and algae, plant health issues are also much slower, this slowness allows you to respond easily to changes.

Tom Barr