I started a 55 gallon tank around 10 weeks ago. I currently have 12 guppies, 2 kuhlis, 2 mollies, and 1 rainbow shark with a large bubbler. I have been having difficulty getting the nitrites down, they have been testing off the charts. I was having some trouble with ammonia and nitrates, but recently they have been testing at 0 ppm
. Yesterday, I performed a 40% water change with the gravel vacuum in hopes of reducing the nitrates. However, when I tested the water today, the nitrates read at around 40-80 ppm
and the nitrites were still off the charts (a very bright purple with the API freshwater kit). I'm worried that the water I am using has nitrites and nitrates in it naturally, but I need to test it to confirm that theory. Does anyone have any suggestions if that is the case or in general? Thanks!