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The hottest most spas will get now days is 104* Jacuzzi and Sundance use to be able to go up to 108 with a special chip but no longer. I think you can thank the government for that one??
You can thank the UL standards.There is a plus/minus on that 104. Â Set spa for 104 and see what it does.A well insulated spa will heat just by running the jet pump with the cover on; the heat cannot escape. Â Try setting at 104 and see if you like it. Â If not, try running the pump(s) with the cover on. Â Check in an hour and see how hot it got.
More likely the lawyers.