I am new to the forums - have been lurking for a bit and have been using the poolmath calculator to help with my chemicals.
I have a inground concrete pool and was swimming around the other day and noticed what I thought was a rust stain. But when I went looking with goggles and felt it it seemed that the paint had cracked and come off. I also noticed the same thing by the drain at the bottom of the pool. I tried scrubbing at it with my brush and it didn't come off. That was when I went and started pressing and using my nail and it didn't clear up. There is also a lot more small spots that look like dirt but don't scrub off. That spot was at a curved groove in the side of the pool at the shallow end. I am worried the pool paint is failing already. 3 seasons ago the grate in the bottom was re-done and the pool was re-painted. I assume after researching pool paints that it was an epoxy paint but I wasn't present when it was painted so don't know what they used.
Can you help me determine if this could be paint failing or if it could just be dirt or minerals that just need like a metal brush or something? I have attached pictures of the spots that were taken from above the water so not the easiest to see. The pictures were from the deep end at the slant that goes down right at the edge. The pictures are after I brushed the area to get anything that was actually loose dirt off. If it is paint cracking is it normal to have some cracking after 3 years? Each season the pool has lost significant water and become algae filled over winter. Then when I fill it back up I shock it and get it clean. Could I be shocking the levels too high? This past season I shocked to a 16 FC - rather my test kit wouldn't go that high but I used the amount calculated on the poolmath calculator. The CYA has been steady around 30 after I added some conditioner earlier this season.
My PH has been running a little high - around 7.8 for at least a month now. I just added some muriatic acid tonight. The TA has been fluctuated between 80 and 110. My chlorine during normal operation I've been bouncing between 1.5 and 3. Still haven't gotten it to stay steady but we don't have a cover and it has been a really hot sunny summer for the past month. Could there be anything chemically wrong causing it?
Thank you very much in advance. I wasn't sure if this was the right place to ask so let me know if another sub forum would be a better spot!