Split from this topic. This side conversation has moved away from the original topic. JasonLion
How often are you backwashing your pool? HTH test strips are not the top of the line. HTH was good company until it got bought and sold a few times. Aquacheck is one we like. We maintain about 600 pool customers and don't have a liquid test kit on the place.
Looks like you just need to floc the pool and vacuum to waste once it settles. Backwash the filter, and don't backwash again until your pressure rises 7-8 pounds above clean pressure.
Could be sand is worn out. It will usually last 5-7 years on chlorine pools. You can test by opening the filter and roll some between thumb and forefinger. If the sand 'flops" it is OK. If it "rolls" it has worn and rounded the corners off and is wore out. Sand is cheap. If you have any doubts, bug some good filter sand and replace it. It has to be filter sand, not the playground sand you buy at Lowe's or Menards.....