I'm new to the forum and newly setting up a 56g tank after a 20 year break. I am on day 7 of a fish cycle with 7 black widow tetras and a fairly well planted tank.
My readings for day 1 to 6 have been 0 for NH4, NO2 and NO3.
Just tested again this morning and I am zero for NH4 and NO2 but showing 20ppm for NO3.
Ph started out pre-fishat 6.8 but holding at 7.0 and GH is about 60 after adding some hardness salts, kH is 0.
Can I have advice about where I might be in the cycle please? I understand that plants can absorb NH4 so that the cycle goes faster? Otherwise I appear to have gone from 0-100 in one night? Isn't the cycle also over when NH4 and NO2 return to zero? What about when they never went up though?
and also, am planning on doing first partial water change tomorrow morning (saturday) but with nitrate at 20ppm should I do it today?
ETA my tests are working as I have also tested on a goldfish bowl where NH4 is rather high.