After about 6 months, the GFI started blowing all the time. Turned out the heater element had taken on a leak and started blowing the fuse. They turned down the warranty because they hid behind the claim that we didn't maintain the chemical balance properly. Bull, it was maintained professionally on a weekly basis. They wanted $400+ to fix it. I called the manufacturer of the brain box and for $79 I got a new heater element.
Took my time and drained the spa. Four screws open the box. Then remove the flex hoses going in and out of the box. Unbolt two large chome nuts holding element. Take element out and replace.
Next problem we're now having is the jet heads keep coming out. The store who sold it to us is too far away. So, I'm dealing with factory direct.
Southwest is in Oceanside California with phone number of 760-450-0066
Hope this helps.