I'm planning to install a small new AG pool. in a couple years, I'd like to get a larger AG or maybe an IG. I want to size / buy a sand filter and pump to support the larger pool. I will also be installing a solar heating system that will be on a roof 25' above the pump. How do I calculate the appropriate size of pump / filter? how much pressure is lost to the filter, piping, etc? Any assistance greatly appreciated.