are u kidding us? I cant believe these posts even exist anymore. If you use "BIO SPORA" and u have ANY problems or lose a fish I will buy u a new fish tank my friends. The folks at Marineland labs have done all of our homework. Dont let anyone tell you any different,The stuff works just as stated and if you hear differently then that person has either NEVER USED IT or they work for the competition. Forget "cycle" cause that is just crap that supplies the bacteria that will have to build up in your water over time so that the bb will START to establish. With"BIO SPORA" you WILL wake up the next day with an established bio colony cause that is what it contains.... It is refrigerated because just as in our aquariums where temperature is key the cold water keeps the bacteria dormant or asleep and untill the temp rises these bacteria are dormant just as what accurs every year when temp drops in the natural environment, Don't take my words for granted , damn, just look it up online I'm not talking shi# this is fact so if you dont look this up you are keeping yourself ignorant to the truest form of the word and you will just not know the facts of the matter. This crap has been out for YEARS and I cant believe that people are still cycling their tanks the old way. OK, I'm done ranting but if people are still posting with cycling questions then I would have to say you are just wasting your time.