We got a 3/4” hose instead of 5/8” garden for this pump, but we had time for it.50 50 water and bleach and brush it. You always want to clean 100% some liners will show black mold thru the liner and green algae too on white background. Good shape overall from pics. For future record a cheap sump pump with a 1.25" outlet or larger will empty a pool in a few hours. The drop in pump with garden hose is very slow the hose chokes off the flow rate
Did that last night. Nothing left on the bottom I could see. Chems look pretty balanced, though my chlorine must be degraded as adding it didn't give the kick up to where it should have been.Brush it around until it dissolves. CYA is mildly acidic. I wouldn’t want it to bleach your new liner.