This all started last year when I changed the sand in my Hayward S-210T sand filter and replaced it with zeolite. Since that time, the pressure does not increase on the sand filter to indicate the need to backwash. Instead, I know I need to backwash when the level starts dropping in the pump filter basket. I know that air in the top of the pump basket often indicates a leak on the suction side of the system, but several things lead me away from this conclusion:
1. I have isolated the main drain line and skimmer line separately and the amount of air does not change.
2. The level in my pool is not dropping other than the normal small amount expected for evaporation.
3. We recently had a power outage that lasted at least 4 hours and the pump never lost prime and started right up when power was restored.
The pressure gage is working fine because I replaced it just last year and the pressure I see is what I would expect for a clean filter for any given pump speed.
Also, I donít know when this next issue started, but I bought a robotic cleaner this year and noticed that it picks up about a half cup of sand (maybe less) if I run it every day. How much sand was in there to begin with and what percent it is picking up each time I don't know.
What is going on here? I know that the sand entering in the pool probably indicates a broken lateral in the sand filter even though I was extra careful when I changed the sand and followed the proper procedure (add water first, cover the standpipe, etc.). It is one of those folding lateral assemblies so I could kind of understand if one of them had been damaged when I folded them up to remove the whole thing from the tank.
The sand filter is a dozen years old, so my question is should I replace the lateral assembly (about $75) or do I need to replace the whole thing (several hundred dollars)? I replaced the spider gasket about 3 or 4 years ago and really hadn't had any problem at all with the filter until I replaced the old sand last year. If it was just the sand blowing into the pool, I would just get the lateral assembly, but I donít understand these other things I am experiencing.