Hi I have a 15' AG , Hayward Sand Filter S166T and Power Flo 1Hp pump. We needed to replace the skimmer and did it last evening so pool just used for first time this season. I put in a knee hi stocking and everything was fine. When i checked this AM the skimmer basket was upside down and no knee hi. Everything seems to be running ok, there is good pressure from return and into skimmer but it won't backwash very good and there is only 2 lbs pressure. I don't know what the pressure was last nite because the gauge was broken and just put the new one on this Am. Help.