Black mold or something else???
I have had hot tubs over 15 years with no issues. My present tub is a dimension one Lotus Bay. After 6 months I started getting black spot and steaks at the water line. I rubbed around the lights and my finger had black stain on them. Bleach did not remove the stain so it was not mold. It was the light seal / o rings wearing out. I called the Dimension one stated it was from not keeping the water balanced. They recommended putting silicone around the lights on my new tub.
My water is always balanced. I did put silicone around the lights and the problem went away for a few months but came back. Dimension one refused to honor the warranty. Did the manufacturer of the o rings change the formula to what ever raw material they could find during this shortage of supplies?? Who knows but all he manufacturers will blame the water balance.
