Not to get off topic, but how does a tree cause you to need to SLAM?
The tree overhangs the pool. Last fall we had funky weather that caused the pool to freeze over before the leaves dropped. Aster the leaves dropped we had a warm spell that let the ice on the pool melt. Leaves sunk to the bottom and the pool froze over before I could scoop them out. Once it thawed for good this spring the water was a nasty black. Scooped as much as I could out with a leaf net. Water went from black to the green in the pics posted.