_Maq_
Member
That seems too much. Mind you, nitrate should be in some relation to ammonium and nitrite you had measured earlier. Nitrate is a bit heavier than nitrite, but if your nitrite spiked at, say 10 ppm, you cannot have as much nitrate.and 160ppm+ of nitrate.
Like I said, all these nitrate tests are very unreliable. Among other things, some of them must be read at exact time - definitely not a day later.