The inside of my skimmer has black marks above the water line. I tried scrubbing it with a dish brush I bought for tough to reach spots in the pool and they didn't budge. I'd read on here that pucks can remove some stains, so I tried it. I have a small bucket of pucks I use at the beginning of the season when my CYA is near zero and the water is too cold for the SWG.
The puck removed the stain. Now two questions:
1. What does it mean that the puck removed the stain? Does it mean it's algae or just that it needed to be bleached out?
2. The pucks are stored in the shed. We put some mothballs in the shed to keep the mice away who had chewed 3 holes in our winter cover last summer. The puck started to stink of mothballs once it got wet. It continued to smell (of both chlorine and mothballs, an awful combo) the entire time I used it. Do you think there's a problem? Did I just put the equivalent of a mothball in my pool and, if so, is it an issue?