Little background: My family moved in with my parents couple years ago to help with various health issues. They built this pool in mid-80s; they love to swim - good for them - but are no longer able to care for pool. So I've been helping/taking over where appropriate.
Soooo, last week my dad had a workman power wash the (ancient) wood decking around the pool, then apply a sealer (Thompson's). He applied it with a sprayer. Enough got into the pool that it collected at the waterline and is now a gooey, sticky gunk with stuck-on debris, especially cedar needles and insects and other stuff that falls into pool (they have nearly complete tree cover over the pool).
Any suggestions on how to get this off the tile at the waterline without upsetting pool chemistry? And should I be worried about what this might be doing to the plumbing, especially the sand filter? He should have used a roller but he was sort of left to his own devices (or maybe my dad told him to do it that way).