My heater trips the main breaker. If I dial back the temp everything else works. As I increase the temp setting the breaker goes. This just started , tub has been OK previous to now.

It sounds like your heater element has gone bad, maybe even shorted. When you set the temp down the heater is off so the short won't happen until the stat hits its set point and the element gets power. Call your local dealer and price a new element and come back here if you want to try to replace it yourself.

Chances are it is the element, but if you have an ohm meter, it would be a good idea to check for conductivity between its terminals and the outer shell. If not, check for shorts in the wiring to it.