Uummm... is it normal for nitrites to start climbing again after the cycle is completed?
I have been monitoring the tank weekly since the cycle finished (2 months ago) and ammonia and nitrites are always '0'... except for today. They are low (0.1 mg/L) but why are they even there is what I'd like to know!!!! Is this normal? Can adding plants to a tank spike up the Nitrites (seems unlikely to me)? Can me cleaning my filter with aquarium water cause this? Can adding substrate cause this?
To start from the beginning here, yesterday I added 2 KG of substrate to my 32g, as well as some plants. The day before that I had done the weekly maintenance (20% wc, syphon gravel, etc.).