I have had my tank set up for about 5 weeks now, only 2 fish alive still out of 8. My ammonia was 0 and nitrite was 5+ then went down to 5 and then a few days later to 2 and nitrate at 10. I figured I am almost done, then my girlfriend despite my objection brought 3 new fish and put them in the tank while I was at work, for a surprise. So wanting to help these poor guys, did a massive 75-80% water change to try and get nitrites down, well they went from 2 to .50. I was happy about that but then i tested my ammonia and it was now also at .50, fixed on problem and brought an old problem back. The next day my ammonia was .25 - .50 (hard to tell) and nitrite was 1 and on its way to 2 again. I am afraid to do another water change as I dont want more ammonia, as my tap water has 1ppm ammonia in it. I was told that the BB that turns nitrite to nitrate wont grow with ammonia in the system, so basically I restarted the cycle by changing the water. I feel so helpless here, i had made my peace with killing the first set of fish, I just don't know what to do to help these guys.