Thanks, Mark. I'm certainly not an expert on DE filters but I like the results of using one and I'm learning. I will play around with the valve settings this weekend and report back soon. This may seem a needless question but I need a clarification--when you say 'suction side' does that mean the intake side up to the pump itself? Does 'pressure side' include the filter? Regarding the options you listed, I like adding a 3/4 pump best because I find nothing wrong with the 2hp. Have a good weekend! Hal