Need some expertise before I call a repairman. Yesterday the hot tub circuit breaker kept shutting off. About 3 times yesterday in a 2 hour time period. Tonight my husband and I had just got in it to relax and it tripped again. I went and reset it, then climbed back in. It was making kind of a buzzing noise. I then turned the jets on and it backfired, started smoking and what the heck happened? I am not sure! Heating element? Pump motor, GFCI? Any ideas?

Backfired huh? I have no idea what that even means

But if it started smoking, call a repairman. It probably means some wiring overheated, and is likely melting. It might just be the wire, or there could be a component problem as well.

Backfire as in like a car backfiring. Like a muffler sound. It was loud, then we smelled a nasty smell. The repairman was just here like 3 weeks ago to work on it. It actually worked better than it had before until last night. We actually had 2 speeds on the jets again! Bummer! I will give him a call.

A "hot" wire probably melted and broke in half, moved, and touched something grounded or a neutral. BOOM. Then the smell. Probably just some loose wires and poor connections, possibly bad heater poles.

Good luck