I just started a fishy cycle and used BioSpira about a week ago. I have to say that I'm amazed at how quickly the ammonia and nitrite levels have gone down. I'm at between .5 and 1 ppm of ammonia and not a trace of nitrite. I put the bacteria on the biowheel and two days later, voila! I'm still doing water changes every few days, but I've never had the ammonia get down so fast!