I got your picture, below. (Watermom, don't look! ;-)

The first is a reduced version of your pic; the second is a full size crop (no reduction!) of the only 'critter' that was close to being in focus. I emailed my son, who is a biologist. He looked at them, and after noting that they were small blurs, wrote this:
"your red blurs are not identifiable. probably a thrip (money on this one if i had to choose), but maybe a silverfish-, springtail-, bristletail-, zoropteran-type thing. or a even larva of something else (but i don't think so)"
But, he also noted that your pool chemistry is unlikely to have anything to do with their presence. It may not even have anything to do with the fact that you've got a body of water there. He'll look again, if you can get better pics, but he'd need something that clearly delineates body parts.

Ben

reduced original:


cropped but un-reduced closeup: