Step 1
Turn off the hot tub and disconnect the power from the power cord or at the circuit breaker.
Step 2
Open the hot tub access panel and locate the thermostat, which looks like a control knob connected to a copper wire.
Step 3
Rotate the adjustment screw on the bottom of the thermostat with an Allen wrench. Turn clockwise to increase the thermostat temperature or counterclockwise to decrease the thermostat temperature.