Nitrates Dropping...

What’s so bad about nitrate going from 40 to 5?

Stress on fish... Or am I wrong with that? Ideally nitrates would be around 20ppm. Dosing with liquid ferts (from my understanding) will raise nitrate levels, thus my tank has always been about 40pp.

 

Stress on fish... Or am I wrong with that? Ideally nitrates would be around 20ppm. Dosing with liquid ferts (from my understanding) will raise nitrate levels, thus my tank has always been about 40pp.

Yes you’re wrong with that. A drop from 40 to 5 in a week will not stress fish. It will actually be very good for them. Ideally nitrates would be zero. 40 is a bit high for most fish and will contribute to chronic stress (ongoing low level stress). If I had 40 I would consider that an emergency and reduce it to less than 20.

The first thing to do with an anomalous nitrate reading is to check the test kit. The reagent#2 bottle needs to be banged against a hard surface for every test...

 

Dosing with liquid ferts (from my understanding) will raise nitrate levels

Only if they contain nitrogen. Usually only npk fertilizer and all in one fertilizer has it. Someone correct me if I’m wrong

 

It's not too much of a drop from the fish's prospective. I don't dose nitrogen in my tanks, so can't comment on the rest.