There seems to be alot of variation in the ceramic disks on these defussers, my dymax is really below standard as far as the size of the bubbles are concerned.. having a tank only 15" deep means that there isnt alot of time before the bubbles get to the surface, even though when they do, they run into the outlet blowing htem about, but even so, I still get alot of loss.

The spiral, when it works, does nothing more than look pretty really, its impossible to count bubbles with it. To be honest, I put mine as low as possible in the tank, so you cant see it anyway. Ive ordered the rhynox 5000 now, so as soon as it comes, ill soak the dymax in bleech, and throw it into storage.