Hi, I hope someone can help me out. I have a 6 year old cal spa that keeps returning to an FL on the display. According to the owners manual this means the filter is clogged, but as far as i can tell it is not, although I dont know when it was last replaced. I can pull the fuses to cycle power and it will reset, and run its normal filtration cycle, but then goes back to FL. Occasionally it will run again on its own but not reliably enough with winter coming on. Also seems to go back to FL everytime i run the high speed jets. Have to pull fuses again to reset. Do I need a new filter??? Or is it probably something else?

Try running it without filters, sometimes a filter will look good but it is reducing the water flow and gives the FLO error. The other problem could be the Flow/Pressure switch. Try running without filters first.