OK so I was taking care of a friends pool and they wanted to save by having me do it every other week. Finally told them NO, all or nothing. Got algae cleaned up (so I thought) and also was finding DE coming back into system. Had torn and broken grids. Cleaned grids while waiting for new ones to arrive. 4 days later went to put new grids in and old ones were covered with green algae again. Figured after putting in new grids, cleaning EVERYTHING I could see and recharging the system I should be good to go. It has been 2 weeks now and I still am getting green in the pool. Chemical and numbers are all good. I have brushed, vaccumed and backwashed constantly. I cleaned the returns, skimmer and lights. Is there something, somewhere I am missing that could still be holding onto some algae????