They say that any NO3
at 40 + can have a negative effect on corals and fish.
is a good way to keep NO3
in check as well as a refugium. Before I added a fuge on my 125 reef my NO3
would run between 5-20 before water changes would bring it back down. With my fuge (knock on wood) my No3
is at 0 and I go several months between changes.
will help keep NO3
in check and lower it over time.
5-10 is good IMO
and nothing to be alarmed at.