I was discussing with friends my spring opening in progress and the question came up about why my pool's pH drops during the winter.
Normally when I close in early October the pH is at 7.5. When I open in early May the pH is usually 7.0 - 7.2.
Despite being covered with a solid cover (actually solid tarp style cover over a mesh safety cover), there is a bit of dirt, debris, and lots of dead worms/bugs (yuck!)/etc in the pool when I open.
My theory is the decomposition process of organic matter in the pool is lowering the pH. Am I on the right track, or is something else going on?
I don't see this as a problem, just curious and want to learn.