Honestly, I use it in ALL of my tanks, and my tanks are pretty stable most of the time. I use the Special Blend, The Water Conditioner (Heavy Metal Detox), and Nite out II for ammonia and nitrite detoxing. I use so many becuase my tap water shoots around in ammonia levels, and the Aqueon is what I have used for the past year or so, and no problems, and then one day I did water change in all my tanks, and did water tests a few days later, including the new snail tank i had up, and nothing seemed to help but constent water changes and different additives. I still need to check parameters in my 80cichlid since i just re set it up and didn't have time to cycle, but so far levels are pretty low like .50ppm ammonia, and .25 nitrite, and 10-20ppm nitrate. I had a fish emergency while adding them back into the tank, and unfortunately shocked about 5 of my good fish and the rest of fine, but i had to remove about 27 gal of new water and reintroduced about 23gal of old water, but that was 3 days ago, so i added water (rather than doing a water change, since it was low still), and added amquel (from LFS) for the 5 extra gallons i just added.