I think something else may be going on here.
I was in the pool this evening. Same brown spots on the floor. Not slimy and they just dust away.
But to the weird part. The water feels funny. I can't really explain it but something is odd about it. Also I noticed if I took my hand underwater and clenched a loose fist, then opened up my hand as it was coming out of the water the surface tension started to form somewhat of a bubble. It would not form into a bubble but the water sort of made a film from the pad of my thumb to my finger tips as they were opening. I know, hard to explain and probably harder to understand but very strange. Then this happened, my son was saying the water tastes bad. Sure enough, I took some in my mouth and it was bad.
2120
FC 10.5
CC .5
TA 110
PH 7.8 - 8.2, hard to tell at night in the house.
CYA was 40 my last check. 9 days ago. A couple inches of water replacement since then.
FC seems to have dropped a bit more today than usual. No bathing load and a cloudy day.
64 oz 10% liquid chlorine added to bring the FC up to 17.