I drained 75% of the pool water to lower CYA and CH.
Water is clear. Scaling with yellow algae imbedded.
After replacing 75% water:
Water is clear. Yellow algae still present, but seems reduced much.
added dry acid to reduce the pH. (target 7.4)
added chlorine to shock level. (target 15)
Leave the fountain on to aerate.
Leave the pump on.
Will brush once a day.
Am I on the right track? Thanks everyone for your inputs.