Sounds pretty standard and not specific to Future Spa. What's could be happening is your MPU board is not getting consistent voltage, so it resets or locks up.
Likely culprits are power driver board (bottom right of the head), solenoid driver board (upper right board) or a connector somewhere. Here's a link to a repair guide if you feel like tackling the problem yourself. I'd follow this and check for voltages at the test points.