I found the curve, currently the guage is showing about 10psi with no load so I am guessing about a 6.5 psi loss which should leave me around 4.25 cfm. From the little bit of research I have done that seems like a little much. As long as over aeration will not hurt anything I think I should be in good shape. What should I do in the winter months when the water freezes? Maybe only aerate a couple hours? I have read a little bit about over cooling and defently want to stay away from that as well. I am using a 9" round sone as my diffuser.