I'm going thru new tank syndrome. I staretd a 30 gal tank about 6 weeks ago and went overboard with the feeding of my 3 mollies. I probably added too many fish too soon and now mt fish have been dying one at a time for the past 2 weeks. The amonia levels peak and poisoned the water. After numerous wtare changes and some chemicals to bring the amonia level under contriol, I now have toxic levels of nitrite. I'm continuously doing 30%-50% water changes and may gradually get my tank under control. Do these bacteria in the pet stores do any good? Any other advice to get me thru this trying time?