First off this has been a great summer - first full summer with the pool and this method makes it easy to maintain.
With that being said we always had some small accumulation of what looked like dead algae each day. The numbers were perfect always within spec. In the last week or two I made a comment that the water doesn't seem to be as clear as it once was. Checked the numbers no CC everything is just right. Today I got home from a trip. The accumulation was significantly more. My DW has said in the past "maybe its the ladder and those bricks that are in there for weight". I disagreed - the ladder is always under water - in the good clean chlorinated water. How could anything grow in there. Today I gave in. I pulled the ladder and the bricks (they are in there for weight). Yep lots of green in the nooks and crannies of the ladder and the bricks feel slick as well. I just brought the pool up to SLAM level - glad I had this site and am not depending on the pool store. If I did I would be expecting a truck load of phosphate remover.
I know you like photos so here is the ladder and the pile of bricks. Enjoy.