Thanks for the good advice. Unfortunately these Sea Recovery systems use what they call an "Energy Transfer Device" or ETD. There is NO separate low pressure (or feed) pump per-say like on some systems unless you think of the ETD as the high pressure pump. Our system has a Diaphragm style high pressure pump made by Shurflo. This feeds the ETD. The ETD optimizes/augments the pressure and supplies the membrane. The whole arrangement is controlled by Sea Recovery's electronics (PCB). Whatever we use in the future when we "customize", it will have to work with the controlling interface of Sea Recovery's controller PCB. OR we just dump the PCB too and re-invent a something. It can be done but we thought we would try and work with what we had first. AND let people know about Sea Recovery and their poor commitment to customers after the sale: for this single missing factor, none of this would be happening.