Water Maker Pumps

[Dev0n60]

Anyone have info/solution for HRO Sea Recovery supplied High Pressure Pumps with their 12VDC systems. We have a 200 gal/day system that came with a Shurflo industrial style HP pump that feeds what Sea Recovery Calls a 'Energy Transfer Device' (ETD). This in turn supplies the membrane. The problem is after every 250 or so hours, the pump performance starts to diminish. We are on our second pump now and the performance is dropping off just like the first pump did. We have contacted Sea Recovery and got the run-around. We contacted Shurflo and they told us these pumps will not perform under constant loads for more than 250 hours because the parts inside the diaphragm pump start to stretch/degrade. They suggested we order a lot of spare diaphragm and valve assembly kits. To keep continuously replacing the the parts when we see performance issues.
Does anyone know of any other way to go with this system so that we are not subjected to fiddling with it so much?