I just installed a series of 10 solar panels on the roof of our house to warm our ~500sq pool and spa. So far, even on partially sunny days, I've seen an increase in temperature of 5-7 degrees, but I've noticed that this temperature water goes down about 3 feet, beneath which the pool remains at its original temperature. Once we start swimming, this largely mixes out, but I'm wondering if there is something I should be doing to more evenly heat (or for that matter filter) the pool. I have two returns from the pool, a skimmer and a main drain; each should pull about 50% of the volume. I have a variable speed pump that I'm currently running at 1750RPM; this seems to keep water flowing through the panels on the roof with a filter pressure of 9 or so. Increasing the pump speed does warm the water a few degrees more, but has no effect on the thermoclime.