I've had this showing up in the water for the last four days or so. It's on the bottom of the pool, mostly along ridges in the liner. About 11pm two nights ago, my numbers were these:
CYA: 60 (though I've learned to do the CYA test better since and think this was a little high)
Based on the CYA of 60, I decided to raise the FC above the shock value of 24. I put in 363oz of 8.25% bleach to raise the FC from 7.5 to 25.5 (went a little high for convenience of dumping in three full 121oz jugs). That was about 11pm that night. I checked the numbers the next day (yesterday) at 11am:
Not much of a drop in FC or increase in CC. Weird, right? Yet I keep having to vacuum this stuff off the bottom of the pool twice a day. After that test, I added 58oz of 31.45% muriatic acid to drop the pH down (and the TA a little).
Yesterday was a really sunny day all day, so I expected the FC would drop. This morning at 11am, the numbers are:
Yet the pics below are from this morning. Any suggestions?