Rolf Hagen "Cycle"

From what I've gathered from other's test--yes, and no. It does contain bacteria that will consume ammonia, but a) they often sit on the shelf too long and are dead when you purchase them. b) if alive, the strain of bacteria provided is not the same as those that can and do establish themselves in the aquarium--meaning they won't cycle the tank, just consume ammonia for a brief time and time, requiring constant replacement (impractical, IMO). c) Cycle introduces nitrates to your water as well, requiring more frequent water changes.

Bio Spira is the only product I'm aware of that has any reputation of reliability and effectiveness.

O-girl has hit it on the head. The stuff is pretty much worthless, IMO. Save your money and do water changes to control ammonia/nitrite during cycling. Lots of us have tried this stuff and found it to do little or nothing to help cycle a tank.

Jim

One thing I'm seeing at our store is, for whatever reason, your tank gets out of whack and folks use this in an attempt to "help" out the tank. All I'm seeing is water tests with screamin' high ammonia and nitrites that take forever to straighten out. I told my employees to stop recommending it.