Hi Jeff
Are these your water parameters? Yes
pH: 7.0
Ammonia: 2ppm
Nitrite: 0ppm
Nitrate: 20ppm
These look very strange. There is clearly some nitrate, so some ammonia is cycling in nitrite and all the nitrite is cycling to nitrate. It usual for the ammonia to be getting to 0ppm before the nitrites though.
A few questions.
- What size is your tank? 60 Gallons
- What filter do you have? Is it suitably rated for the tank? see attached pic
- What fish do you have in there? plecos, mollys, tetras catfish glow fish
- Are your fish looking healthy? Is the ammonia resulting in any visible issues for the fish? 1 fish doesn't look that good. 2 has died a week ago
Tested tap water Ammonia o nitrites 0 nitrates 2.0
A few potential causes.
Perhaps you just have an unusual cycle, keep up with testing and water changes whenever you see detectable ammonia or nitrate. If you havent already done so, either get some established filter from somewhere or dose with some bottled bacteria.
Perhaps your tapwater is putting ammonia into the system. Can you test your tap water for ammonia. If ammonia is showing, it is likely to actually be chloramine, which some water companies use instead of chlorine. API test for ammonia is actually a test for chloramine, bottle #1 turns the ammonia to chloramine and bottle #2 tests for chloramine.
Perhaps your filter isnt suitably sized and doesnt contain enough biological media to support enough beneficial bacteria to fully cycle out the ammonia.
I would also test some bottled water for ammonia, just to check that you dont have a defective test kit. Bottled water should be 0ppm.