CFM at the diffuser is regulated by the valving on the pump manifold. You have control of CFM. Pressure needed to operate the diffuser is determined by the depth diffuser is located. Deeper it is the more psi needed to have it produce bubbles. For 2 diffuser set up, establish location of diffusers. With system running, fully open deepest valve diffuser - get it bubbling max. Then gradually open shallower diffuser until it and both diffusers produce bubbles that you are satisfied with. All you are doing is allowing air to escape from deep diffuser to shallower diffuser.


aka Pond Doctor & Dr. Perca Read Pond Boss Magazine -
America's Journal of Pond Management