My pool is ~18m old. I seem to have these rust color stains that keep popping up. I scrub/brush but they are still there. Noticed more today. My CYA was really high and I guess had been high for awhile. Over the weekend I did a partial drain of the pool and will be looking at getting pool water tested today. Anyway to figure out what these stains are or how to get rid of them? TIA

I have a chlorine pool and use test strips a couple times a week. Other than CYA .... all numbers have been good with little adjustments to chlorine/ph. I also started having a yellow algae problem which lead me to pool store to have water tested and to discuss treatment. That is when I was told CYA too high. UGH. But these stains started showing way before my algae issues.

I tried to post pics but it keeps telling me there is an error..?