Ive been battling this brownish looking stuff (see pics) accumulating on the floor of my pool for a few months. Although the pics makes it look more green then in real life. Its only on the floor, not the walls and accumulates in the ripples of the liner very slowly. I have vacuumed it out to waste 4 times now. Initially I thought it was sand that wasn't filtering, then I thought it was mustard algae then I thought it was pollen. I officially have no idea what it is.
That's when I found this place, read every section many times and took things into my own hands. Whats screwing me up I think, is that I went away for 2 weeks and relied solely on chlor tabs in my chlorinator (which I don't use anymore normally). My CYA is now 90 and I try to keep my FC up around 10-12
My test this morning
FC = 8.5
CC = .2
TA = 100
PH = 7.5
I cannot get my CC to be 0. It has been .2 for a few months however the SLAM process says that once under .5 you should be good. I can tell you that I lost 2ppm chlorine over night last night. from 10.5 to 8.5 so im not sure if that indicates a problem. The brown stuff is slowly reappearing again after my last vacuum and when I brush the floor of the pool some spots have a little cloud of stuff come up even with no visible algae present.
Any suggestions. Should I SLAM it again and wait till the overnight change is only 1ppm? Should I drain the pool to get the CYA down first?
thanks for the help.