If you are careful with your nitrate testing, it is fairly reliable using the API test kit Liam. Each 1 ppm of ammonia is expected to show up as nitrite at 2.7 ppm or as nitrate at 3.6 ppm. If you do not see either chemical showing up in your tank it is time to look elsewhere to find what is removing your ammonia. In my heavily planted tanks, it is not at all unusual for my plants to remove all traces of ammonia. When I try to balance the equations related to ammonia conversion, nothing really balances. The only conclusion that I can draw is that the plants have removed all nitrogen as fertilizers and that there is no need for me to cycle the heavily planted tanks for the fish's welfare. After a 6 months time period with no water changes and a heavily populated tank, I find nitrates in the low 10 ppm range with no nitrites or ammonia. That is not at all typical of any regularly cared for tank. In a normal tank you can expect to face a nitrate build up from ammonia conversion that amounts top 10 ppm weekly or even more. You would remove that nitrate by doing water changes. If your tank is heavily planted, with very healthy plants, your water chemistry may be fine. It would not indicate a cycled tank but might possibly indicate a tank that can function without the traditional cycling being done first. You need to examine the actual conditions in your own tank to decide what conditions you are dealing with. If you do not have very heavy plant concentrations, do not take this as an excuse to say that you need not cycle your tank. Far more often your chemistry results would mean that you are not doing the best possible job of measuring the various nitrogen compounds in your water.
