What's the lethal change in nitrate lvls?

[KeIgO86]

hi, would like to ask whats the lethal change in nitrate levels, as i read in some article that a large change will kill the fish. what i read was a suddenchange of 0 to 20ppm will kill the fish, but 20ppm of nitrate achieved by a slow gradual increase won't harm the fish at all. because im going ns soon, can only dose fert on weekends and not daily anymore.

[bclee]

No... dosing 20ppm of NO3 will not kill your fishes. You can safely dose your ferts weekly.

BC