I tried a fishless cycle and never got a reading of more than .25 nitrite after 3 weeks. I gave up and changed the water until it had 0 ppm ammonia let it sit for a couple of days then bought 2 zebra danios. I have had them for a week. Since then I have had no ammonia or nitrite readings. Today I have a nitrate reading of about 10ppm. When will I know if my tank is cycled? Is it possible that the bacteria started when I tried the fishless cycle and getting the fish helped it? at this point I don't know what to look for etc.