My controller is a Selectron 500 for a Vita Spa, not sure the model #, it's flashing 'FLOW' and the temperature has dropped down to about 80 degrees, and it wont get back up... What should I do?
Any advice would be appreciated.
Thanks!

FLOW usually means low or no circulation. Try this: Shut off the breaker, take out your filter and open up your breaker. If the code is gone, your filter has to be changed. If the code still on, you will have to change the pressure switch.