Hey guys I have had an issue with these dark spots in the pool since I've bought this house and they seem to be multiplying. I have tried vitamin C tablets on them and it has had no effect. I purchased the following device to use with muriatic acid but that also has had no effect.
I used a stainless steel brush and brushed like crazy, it did not do a thing on them. My pool was built in 92' I notice when I use the larger 18" stainless steel brush I find sand/ pebbles in the robotic cleaner. Does anyone else have this problem with pebble tec/ diamond bright?
I tried a thick sharp edge paint scraper on one of the spots and it lighted up drastically by just scraping at the top layer. Should I try a concrete file and see if I can file the spots out? Is this advisable?
Below are pictures of the spots and the tool I am thinking about using.
Also below are my pool levels (I just got done slamming)
I plan on lower TA once FC is lower.