NO3 still high after water change

[twilliard]

How low should nitrate be before adding inverts and fish.

No3 within itself is not a killer

 

[Randy Holmes-Farley Verified Community Expert]

How low should nitrate be before adding inverts and fish.

Well, if it is below 30-40 ppm (very roughly) , the concern is not so much the inverts and fish but algae and browning of corals.

 

[_Conway]

Well, if it is below 30-40 ppm (very roughly) , the concern is not so much the inverts and fish but algae and browning of corals.

What effect does elevated levels have on fish, if any.
I've read a few articles which state nitrate is the 'least toxic' or safe for 'most fish' makes me curious as to high a fo tank could work at.

 

[Lynn52]

Mine got really high late last year. The max my test kit could measure was 100 and they were well over that. I lost 4 fish (2 tangs, a royal gramma and my YWG) that appeared healthy over less than a week. I also lost several corals I'd had for a long time. The other 5 fish survived. Now almost 4 months later I am getting them down with large water changes but I am not there yet. Currently they are at 25. Critters are all doing well at that level but I still have a long way to go.