I wrote a few weeks ago about my tank killing cory's. Per the forum recommendation i got a good api test kit, and once i tested ammonia, i found out it was 2 ppm. So i've did a bunch of 50% water changes until the ammonia was down to under .25ppm. Now its been a week and the ammonia is staying steady under .25ppm, not 0 though. And the nitrites are staying at 0. Nitrates have always been 0. I haven't added any new fish, so all i have is my 3 guppies in the 10 gal tank. We are feeding every other day just what they can eat. Is the tank just cycling really slow? Or has it already cycled?