This is my first post for help as I have come across an issue that I believe to be monsoon weather related. I have a pool route in Arizona and we are in the summer monsoon rain season. As much as I love the rain, it can cause all kind of chaos for the pools. I have encountered my share of green, mustard, and even the super fun black algae. However this past week I have come across something all together new and never before seen. I have 2 pools in which I have seen this... one residential that gets no use, and one commercial that gets very little use. Both of these pools have water that is beyond needing replacement... the residential has agreed to a draining this coming week and the commercial client will continue to fight me over water change and blame me for his water problems even though I explained 100 times over what his problem is....bad water... bottom line. Thanks to Richard I do understand the FC/CYA relationship as well, however I will not and do not keep the FC levels as high as they require because one it is not healthy levels at that point & my prices are structured for "normal operating conditions". They both have sand filters TR-60 and one is 17,000 and the other is 24,000 gallons.
TEST RESULTS (commercial) (Residential)
FC 5 5
CC 0 0
PH 7.6 7.4
TA 110 100
CH 1300 1200
CYA well over 100 (even did the dilution test, so safe to say well over 200) for both pools
TDS 1800 1920
The problem that has popped up this past week is probably not an algae but not sure. It looks like grey spots that adhere itself to the plaster and is all over the deep end in one pool and in the areas of the steps in the other pool. I thought it was black algae at first but was far to spread out and far to big to be black algae. Yes, I looked at it closely and tried to scratch it off with my finger nail and sometimes it will brush right off and some of it does not want to come off with out elbow grease and a ss brush. For lack of better description it looks like grey snowflakes and the size of the spots are a little smaller than the size of an eraser on the end of a pencil or smaller. I figure this is rain related just because we have had crazy rains this season and both pools did this the same week after some crazy and brutal storms went through town. Any thoughts or ideas are greatly appreciated. Thanks much.