I have been pulling my hair out. Our pool is a 3 month old Pebble Fina gunite pool. I always keep my chemicals in check and check them every day. However, my Phosphates have been high. I have treated twice with PhosFree per Leslie's and use a maintenance dose as well each week. About a week and a half ago, we noticed some gray spots in our pool on the bottom. I have about 24 of them at this point. They very in size from the size of a dime to the size of a pencil eraser. I have been unable to brush them off or sand them off. Since I also noticed a small patch of yellow algae in a corner of my steps that could easily be brushed off, but came back about every 5 days, then I decided to go and have it checked out.
Saturday, we took a water sample in to Leslie's and were told that our Phosphates were once again high(2500) and that the spots were either metal deposit or algae. They sold me "algae control" and told me to brush, super-chlorinate, brush again and add the Algae Control.
I did that with no results on the dark spots. I also crushed up some vitamin C tablets, put them in a sock and left it on a gray stain for about 2 hours. No luck. It cleaned all of the calcium build-up around it, but didn't touch the stain.
I called Leslie's this morning and was told that they think it is black algae and that I shouldn't try to lower my phosphates right now until the algae is gone. They told me to keep my chlorine high and brush 2-3 times per day vigorously. They told me that it could take up to a month and we shouldn't swim during that time because of the high chlorine levels.
I am totally confused. Shouldn't I get my phosphates down? How can I do that with a chemical that will actually work?
Is it actually black algae??(I've included a picture, notice I have a lot of calcium build-up).
Will it really take that long to get rid of it? I'm just not sure what to do.
My numbers are:
Chlorine - 5ppm right now. I usually keep it about 2ppm
PH - 7.4
TA - 110
CH - 230
CYA - 40(Leslies) 60(my test kit)
Any help would be great. I don't know if I should call a pool service to come and look at it.