We recently battled a mysterious algae issue with the wonderful help of this forum. We couldn't really find a source at the time despite checking the usual suspects (edges of liner, behind ladder, under ladder mat, skimmer box, pool toys, solar cover).
After great results since our SLAM, we had some sediment returning again! We were so frustrated!
We pulled the ladder, and I noticed that the bricks that we wedged into the back of the ladder in the spaces provided, and as instructed by the manufacturer, were a little slimy. It dawned on me that the rough surface of the bricks, and the nooks and crannies that they hid, were prime algae zones.
The only way for me to get the bricks out was to drill access holes on the front of the ladder rungs, and push the bricks out with a screw driver inserted through those holes.
When the bricks fell out, there was 1/4" of algae having a party on each brick. Every other surface of our pool was spotless, but these bricks were hiding a field day for algae growth.
So, we got rid of the bricks and will deal with a ladder that wants to be floaty. I drilled circulation holes all over the ladder in a nice symmetric pattern. After scrubbing down everything and checking our levels, I think we may be good to go and have avoided any need to do another SLAM, but we'll keep a close eye on it.
Anyways, all that to say what you all probably already know.... Watch those bricks.