First off thanks to everyone who contributes to this site. I would be a lost new pool owner if not for the resources here. I've spent the first three weeks with my pool getting the chemical balancing in check and now that it seems to be dialed in I would like to address the staining on the plaster. The plaster is 5 years old and there is extensive staining particularly in the deep end and on the steps. Dropped a trichlor puck on them yesterday and it did nothing. Rubbed a few with vitamin c tablets and the stain does go away. So they are iron stains correct? Some are very large and with it being a big pool I'm not sure I'll be able to address all of them by filling a sock with ascorbic acid and manually scrubbing - although I'm game for giving it a shot. Bigger question is should I just leave them until the fall or spring and address them immediately before opening or closing the pool? I'm asking because if I do a full AA treatment I need to lower my FC level to 0 correct? And I'd rather not risk an algae bloom in the middle of summer with as short as it can be in Michigan. Thanks for any input!