It's funny you mention this today. I need to go and shock ours and test the chemicals.
I would suggest finding your local spa dealer and grilling them for as much information you can. They will have the chemicals you need to maintain your spa at the proper levels.
There are a number of different chemicals to use. Chlorine, Bromine, and enzymes. IMO, stay away from chlorine. It ruins suit, assuming you wear them, and can burn your eyes if the PPM (parts per million) is to high. Bromine is an alternative that is similar to chlorine. We are using a variation that is 100% chlorine free (not all are) and seems to work well for us. You'll need to shock your spa once a week and after each use.
But after all this it is well worth it. We enjoy ours frequently and have had a foursome in the middle of winter under the stars with neighbors about 30 feet away and no clue what we were doing.
