We bought this house last summer, so this is my second season with the pool. I have obsessively read the forums here and have mostly been using the BBB and recommended wisdom here. I've had a recurring problem with algae or pollen/SOMETHING. This has drove me nuts. The guy we had close the pool last summer did a crappy job and we opened to a black swamp full of leaves and seeds. Slowly, shock, the filter, and lots of netting cleaned it up.
I'm in MD and we had a few really bad weeks of storms dropping in lots of rain and with it god knows what else. I have been seeing greenish yellow stuff accumulating in dips and the corners. I would see this all along any non vertical surface. This stuff would accumulate in corners and seems and on the floor and sloped walls but not the vertical walls. I brought up the FC to 14 and brushed the whole pool. The water went from clear to dirty/greenish after brushing, nothing like the swamp we had earlier in the season though. I had remembered the same thing happening last year as well. I had assumed it was algae and shocked it and cleaned the pool thoroughly but it would return clumping in spots every few days or week or two.
This morning, I did a backwash and filter rinse. After setting it back to filter and doing a water test I noticed that all the sudden the floor around the return in the shallow end had that green stuff along the floor clumping in various spots and seems. Before backwashing the floor was clear. This got me thinking that something is wrong with the filter and that maybe the filter needs one of those deep cleans with the hose. Or possibly replacing the sand. (I know sand replacement is a bit of a religious topic around here) I would just do this, but the plumbing doesn't have screw on union joints so I'm doing some plumbing if I have to take the top off. Given how gross the pool was a month ago I can imagine that the filter is really full of ****. I have been backwashing regularly.
I lost 1 PPM FC over night 0 CCs. Should I still see green specks appearing at 13FC and 30CYA? Am I wrong to believe that I should not see new algae on the floor at 13FC/30CYA? I'm color blind so telling green and yellow apart is not easy. My wife said the spots and stuff are greenish yellow (helpful I know...) could this be mustard algae? I understand it requires higher FC levels to kill, but shouldn't it still at least be using up more FC than I'm seeing? I believe my pool is getting dirtier by running the filter longer.
We have a LOT of trees in and around our property. So pollen isn't an impossibility. What would still be greenish at that FC level?
Confused, frustrated, and ready to find money to fill this hole in...
30k gal vinyl
CH was ~100 a week or so ago
TA was ~100 a week or so ago