I bought this house a few months ago with what I think is black algae. My CYA was off the charts so I drained. See this thread for that http://www.troublefreepool.com/need-...ol-t39714.html
Here is my current pool chemistry,
I have been well over shock level for 5 days now (between 32 and 25), and have brushed almost every day with a SS 18" brush. FC use has been very low, I have passed OCLT several days (unless you count the black spots as not crystal clear). Water is cold, weather has been in the 30s at night.
The BA is clusters of small black patches, around dime sized or smaller. They are black and slimy and can be scraped up with a fingernail. I have a lot of it, mostly on the walls and on the slopes to the floor.
First, it is very hard to brush with the big SS brush - it jams all the time, and it is hard to brush well with it - is that typical? Anyone have any tips? On a long pole, it is very hard to brush the stuff on the bottom. The brush just seems to catch on the plaster, and the best I can do, especially on the floor, is kinda drag it back over the floor and it skips along. I can brush well on the upper parts of the wall, but the lower parts and floor are almost impossible.
Second question - even when I brush areas very well, nothing comes off - the spots are not brushing off at all. I get a bit of a pale blue cloud, which I assume is plaster or something, but the spots don't come off. I assume what I am trying to do is scrub off the slime so the chlorine can work, but it doesn't seem to be doing anything.
It might be that some of the areas I have been able scrub well are getting a bit lighter looking, maybe grey looking.
So what (if anything) am I doing wrong? I have been well above shock level, and even the areas I think I am scrubbing well don't seem to be improving much or consuming much chlorine.
When you guys say to brush it, do you mean to make a couple passes over the area with the SS brush, or do you mean to scrub the area for 5 minutes with the brush until it is gone?
No matter how much I brush a spot, it doesn't go away - is that not the goal?
Can I injure the pool by too much brushing?
Oh, if that wasn't enough questions, is my ph higher because of my high FC? Should I add acid to get it down to 7.2 to make the FC work better? Should I add borates??