We had spent a fortune on pool chemicals earlier this spring to try to clear up our (algae first), then cloudy water. Finally drained about 80% of the pool and scrubbed, scrubbed, scrubbed, vacuumed to waste. Filled with new water, but when the pump was running, we couldn't see below the second rung because of the cloudiness. We always run our brand new pump 24/7, and have checked our filter quite a few times. It never seems to get dirty (beginning to worry me). Have been using the BBB method for a couple weeks now -- yayy!! -- and brought our chemistry under control... but still cloudiness. We had parties all weekend, kids nonstop in the pool, so we turned pump off because of all the splashing water/waves - and lo and behold, perfectly clear water - you could see a pin at the bottom. I was thrilled, but told my hubby I hoped it didn't cloud up again when we turned the pump on. Sure enough, it has. This is such a mystery to us... What could make perfectly clear water when still become very cloudy when moving through the pump/filtration system? We have a cartridge filter, so it is not like a previous time when we had a sand filter with a crack in it. BTW, I know I have to tighten up those numbers above but we simply haven't added our chlorine since the parties. Thanks!!