Pond Boss Forums AERATION Systems questions Airmax vs hiblow- small pond

When determining the pump size, you need to add up some pressure numbers to determine what the pump will "see".

A vertex diffuser needs around 1psi to pop the check valve (maybe 2 per Mr Cody - I would like to find out for sure as I do not recall exactly where mine popped open).

With the diffuser at 8 foot deep, that will require and additional 3.44psi. (0.43 psi per foot of the deepest diffuser)

Air line and fittings and valves will add more psi requirements. A simple pump-line-diffuser system would be minimal depending on the line diameter and length. I'll throw out another psi.

That totals 5.4 psi (or 6.4 if the Vertex's need 2 psi to pop). The HP-120 would be putting out about 1.5 CFM at 5.4psi and less than 1 CFM at 6+psi. The smaller HP-100 would be about 1 CFM and 0.5 CFM respectively. The 120 would work for a single Vertex diffuser, but you would not have any room to add another diffuser should you want to down the road (unless you added a larger or another pump). You could move the diffuser up in the water column to lessen the pressure, however. Doing so increases the turnover time of the pond too.