Some time ago I decided to add an ozonator to my spa. I did so because I wanted to reduce the amount of chlorine use. However, after having the ozonator for over a year (replaced the chip a couple of months ago), I now notice a yellow stain on the tub wall (fiberglass). It appeared about a month ago. The stained area is across from where the ozonator ejects into the spa.
However, about 8 months I also began using N2. About a month ago, I replaced it with a new cartridge. The water from the filter and N2 also comes out in the area where the ozonator ejects air.
So I'm wondering what caused the stain, the ozonator, or something in N2?