boy that sure rings a bell. The last thing a dealer talks about is chemicals and care, that's a surprise left for after the sale and installation. The first few weeks we had our spa I was in it for an hour each and every night the first two months. then it all turned to a nightmare! rashes and chemistry trouble. in hindsight it started cause I tried to save money with chemicals I knew nothing about. for instance going away from bromine cause I ran out of sanitzer and didn't like the smell and using the mentioned "non chlorine shock" .

This sounds like a rash from too high chlorine. Start by balencing alkalinity and hardness, then pH. The cholrine, I like to use this combo...Dichlor, Oxy-shock, and Nature 2. Once the first 3 are in line, shock once/week or more if it's used heavily and maintain a residual (1-3 ppm) free chlorine. Nature 2 is good for about 3-4 months...you'll know when you have trouble maintaining alkalinity, hardness, and pH.