Cannondale

Hi! I have a 2009 Jacuzzi J365 Hot Tub. It's used 3-4 times a week. Last night it had F1 flashing (with the temp, which had dropped to 91). The heater obviously not working. I cut the power and cycled it on after ten minutes (as one suggested), no change. I decided the water needed changing and one troubleshooting tip was dirty filters causing this. I soaked the filters overnight in filter cleaner, drained the tub, cleaned it out, then slowly filled it up. After powering it back up, I was deflated to see it still showing F1, but now at 54 degrees and not heating. I then tried to pop an air lock in case that was the issue, removed the filters, stuffed the hose down the filter inlet with a rag wrapped around it to plug and cycled the hose on for 30s a few times, no change. There are no hot tub repairmen available for 3 weeks, and I have a kids birthday party who was depending on this hot tub to host their 7 yr old friends :( Any other suggestions? I opened up the sidewall to check and i believe the circ pump everything is running fine. I'd assume that the flow switch perhaps is not being cycled off? Or I have to take the pump out and check the impeller? The only thing I can think of lately is that some small chunks of rubber from my jacuzzi pillow (disentegrating) were floating around but I had scooped most out, maybe they somehow plugged things if they got in.