Good afternoon! I switched from a bromine/chlorine hot tub to baquacil, and was unfortunately sick for a few weeks and didn't check the hot tub. When I opened the cover, I noticed the waterline had a sticky residue, that wouldn't come off by rubbing with a towel. I drained the hot tub, put in a spa cleaner for 20 minutes, and no real change. After having been drained for a week, the goo is less sticky, but getting it off has been another matter. What hasn't worked - Magic eraser (destroys it), baking soda mixture (might have made some minor progress, but I was worried about abrasion), and CLR spray. It feels smooth and near impenetrable......
Anyone have any tips for cleaning this off?
Thank you!

Anyone have any tips for cleaning this off?
Thank you!
