How long after WC to test Nitrate?

[CoRPS]

How long after a water change will the nitrate test be accurate?

[mavjoy]

I usually wait 3-5 days after WC.

[IslandCrow]

Why don't you just test before your water change. That'll give you your worst case scenario. Personally, I find it more useful to know my highest level of nitrates rather than to make myself feel good knowing what it is best case.

Otherwise, I don't think I understand why you'd have to wait 3-5 days. No more than 30 minutes seems like it should be plenty of time for the new water to mix with the old. Of course, that's going to depend on the turnover rate between your sump and main tank.

[CoRPS]

My nitrates are a consistent 20 and I'm trying to lower them. I'm trying to figure out how much 10 gallon changes in my 55g tank. I know that the highest my trates have gone since the cycle is 20, and the lowest it's gone is 20.

Even after 2 months I still test my pH and nitrates every 2-3 days.

[atvdave]

I'd say 2 to 3 hour's. That should give the new water plenty of time to mix in with the old water.