Sometime in March I noticed the cover had come partially off one spot on the pool. I don't know how long it was like that but figured there's nothing I can do until spring. So I pulled the cover last Thursday and there was lots of schmudge and a brown film all over the bottom of the pool. After starting the pump, sand was coming out the return, that turned out be broken center pipe on the lateral assembly. I found one locally Friday and got the water moving Friday night. OCLT from Friday to Saturday the chlorine dropped considerably. It dropped again Saturday but seemed more stable Sunday morning. After vacuuming Friday night and 3 times on Saturday (once in my bathing suit in the rain) and a whole lot of backwashing the pool was swimmable yesterday. pH is good, TA is good, chlorine seems stable and I'm going to start the SWG this week.