The reviewers also seem to have gone nuts for it.I also used this: http://www.amazon.com/dp/B0002DGKCC/ref=sr_ph?ie=UTF8&qid=1463623007&sr=1&keywords=aquarium+bacteria
I didn't buy it again, as it didn't fit my budget. It is $35 per gallon which treats about 640 gallons. With it treating such little amount of water, which I didn't know at the begging, I can assume that it is made to very quickly cycle your tank, that is if it is as concentrated as I think it is, considering it has an earthy scent.