Cleaning black mold out of a pool

[Prout-1]

This was my experience. I didn’t want to etch the pool due to lack of experience, but I think that’s probably what it needed.

Pool cleaning help

[20200520_105846] [20200521_115446] Does anybody have any ideas how to get this pool cleaner? The stains appear to be from a combination of clay, dead leaves and algae. I washed with 2.5% sh and eliminator 10 minutes dwell with a 500 psi rinse followed by a 1000 psi rinse. Then 2.5% sh with cling on roof wash, with 15 minutes dwell. followed by a 2500 psi rinse, then oxalic acid brightening and a 500 psi rinse. The customer is happy and we had to call it quits due to time constraints. I fee…