Zero No3 on Salifert Test kit is actually not 0.0

[CHSUB]

Turns out zero on hobby test kits is not zero and “bottoming” out nutrients can’t be determined with hobby kits. Imo, eye tests is more reliable: pale colors would be best indicator.

Fauna Marin ICP results: no3 = .1 ppm, Salifert =0.0; po4= .015, Hanna =0.0.
Corals colorful and growing!

 

[Randy Holmes-Farley Verified Community Expert]

I'll just repeat myself that ANY association of a reef tank look with a particular nitrate level as an indication of whether it is a problem or not ignores all the other sources of N in a reef tank, such as ammonia, organics (amino acids and others), particulates, and whole organisms such as bacteria. Those certainly vary tank to tank.

Undetectable nitrate with a test kit can be a serious problem, or it can be OK. It all depends on these other sources.

 

[sixty_reefer]

I believe that’s why is advisable to run a system with detectable residual no3, a minimum of 1ppm is advisable and higher or lower will depend on how experienced are you in the hobby.
At the end of the day you only determining the residual no3 not what the system is producing and using.