Swim Spa- Chlorine

I cant handle bromine on my skin. What would you use with an outdoor swim spa? This is 1762 gallons above ground 14 x 8 foot swim spa-hydopool. In winter I keep at 89-90 degrees and is covered more often so not much sun. I also live in Iowa with cold winters but still swim outside. Summer temp will be around 80 degrees and will be uncovered more often. I just started chlorine a week ago after a drain and refill of bromine. I am using 1 inch GLB 89% trichlor bought from where I bought swim spa. The tablets are placed in a bromine/chlorine container inside my filer. Shocking with 99% dichlor. It has held its ph balance this first week and I am able to swim without rashing. I keep reading bad things about using trichlor in a spa. My situation is in between pool and spa. I'm getting different answers with everyone I ask. Help.....Just purchased in November so I already changed water a week ago.

What is the difference btw 89% trichlor and 99% trichlor. THanks for your info?