I guess this is normal. would running a pool cleaning robot like a tigershark speed up the removal?
Lots of brushing for a few days usually yields the best results.
14100 Gal IG MiniPebble, Pentair Intellichlor IC-40 SWG, Sand Filter, Pop Up Cleaning, Intelliflo VS Pump, Aquacal Heatpump/Chiller, 1/4 Acre Desert Landscaped, Lots of Deck. Built in 1984, updated in 2012 and 2014
"If you don't measure it, you can't manage it!"