Hot tub comes up to temp and then stops heating just before 100 degrees – jets stop working as well?

I recently moved into a house with a sundance 605 hot tub. When I first filled the tub and turned it on, everything worked; the jets came on, air came on, heat came on. The tub proceeds to heat up to just under 100 degrees and then everything stops working. The jets wont come on and the heat stops. I know the tub is still getting power because lights work and you can hear a relay or something clicked when you try to turn on the jets and the air. I checked the one fuse visible and hit the reset switch on the heater but nothing seemed to work. It has done this twice – the first time I messed with it for a little while, then I figured something was broken and let the water cool down. I decided to try again a week or two later and it did the same thing. I turned on the breaker and everything was working properly again. The tub again got to about 100 and everything stopped working. please let me know if anyone has any ideas

Sounds as if the thermostat is opening all of the power to your tub, the lights would stay on because they do not run through the thermostat. This would be the reason why you don't get above or to 100 degrees.

Hot tub comes up to temp and then stops heating just before 100 degrees – jets stop working as well?