Grace, it's a long story. It all started off with my PB specing a 2HP northstar pump. I told him (after posting on the defunct pool forum) that I thought that pump was way too big. He said that I have 8 returns, a 21 foot weeping wall and a spa jet all tied into my filter. My pipes are 2-1/2" and based on feet of head I can turn over my pool in less than an hour. I run my pump twice a day for an hour and a half each time which works out to over 3 pool changes a day.
Initially, he had it running 6 hours a day and my Polaris running 3 hours on a 1HP booster pump but after seeing my electric bill I decided to tone it down. I have had no problems to date so I think it is working so far.