Welcome to our forum.
Chad,For what ever it is worth, I had those too, right before I got the hot tub dermatitis. My dealer thought it was possible that it was an algae. I majorly shocked and they disappeared. Mine kind of looked like rust spots.
I've noticed these small brown dots on my spa's shell.
BILL !!!! 8-)
Chad, Sounds like black algae, I have had it in our pool. I asked a question about it here to all the pool/spa dealers. The best way to get rid of it is to scrub the area where you see it really well, supposedly black algae can attach itself right into the shell. Then raise your chlorine level for a while to help kill it off. There are algicides available for pools that may work also although I'm not sure about using them in a hot tub. If your near a water change maybe you could circulate an algicide though your tub overnight just before draining it. Good luck and Happy Holidays
Dichlor Shock, with the lid closed. If you can, give it a scrub first to open the surface of the stuff up a bit.After the shock, you should rinse the filter. 8-)
Tileman, are you still experimenting with less or no dichlor after every use? Maybe you can shock and go back to your old routine. Let us know how it goes...........