The end of summer and the pool is closed - but the problem has still not been solved. I contacted Hayward and received an email back within a day or two. They suggested that I add some diatomacious earth to the sand filter to filter out the small particles. Then, at my urging, got them to admit it could be a problem with the slector valve. I ordered a replacement valve seal (which is half of the valve and cost $42). Replaced it, checking for any cracked or broken parts when I disassembled it. Put it all back together and - you guessed it - no change in the symptoms. I am seriously considering buying a new filter before next season. This is only my third filter for my pool, and we have had a pool for 27 years now. This is the first real "unsolvable" problem I have had.
The problem is not a filtration problem. The filter works fine and the water is always clear. The filter just seems to release some debris back into the pool when the pump is restarted after being shut off for a period of time, even if I have properly backwashed and rinsed the filter.
