Thanks, Mark. That helps a lot.

Yeah, I know the pump is oversized -- even the solar guy was amazed at how big mine was (so to speak :>). It was just what they put in.

I had figured with 40 GPM it would turnover in six hours, so your estimate of 2-3 hours is probably right on the money. What I *don't* understand is whether I should be running the pump that little -- something doesn't seem right.

So... I guess my next question is whether if turnover is 2 to 3 hours, is it actually possible to run a pump that little? Is there not some sort of minimum time a pump needs to run regardless of the GPM, or is this just simple math and therefore that's it (I should also mention our water is always sparkling clear -- but I *was* running at 8 hours per day and then cut it down to 6).