Jimgurzler

Hi folks I have a 99 grandee and my gfci trips after tub gets to temp. I have a trombone heater that was replaced a couple years ago. The tub gets to temp fine but at some point trips the breaker it doesn't trip the high limit switch (blinking red power light) it trips the breaker. Tried running without filters just in case and also Ohm tested heater 10.5 ohm so wondering If thermostat is bad? I see ozonator could be an issue will try disconnecting that but wouldn't mind some direction from you guys. Thanks