With the Vertex I get 10psi+ in or out of the water. At the pump or at the end of the line.
With the old stone diffuser I get 1psi or under out of the water and around 5psi in 9' of water.
Notice on this page the water volumes moved are based on 1 cfm per disk. I'm wondering if you just have a lot more air than the orifice in the diffuser is expecting.
Lifting rates Like Bluegillerkiller said, call Ted.
