hyperman

We just moved into a house a few months ago. Been using the hot tub but then found out the water had not been changed in a year. No issues up to this point. Drained the spa and filled it up from our well. Water at 54 degrees. The circulating pump is running and the jets work fine but the heater will not start up. The green light on the side is flashing and the power and ready lights on the LCD are flashing. I have tried to power it off twice as it indicates it could be the heater high limit thermostat has tripped. I have drained some water and I am adding some hot water to try and bring the water temp up some. Trouble shooting also indicates a clogged filter. Filters are basically brand new. I am concerned that maybe some sediment from the well might have got into the system and it thinks the filter s are clogged. I also see it could be air lock? How do I resolve that issue if it is air lock? Any suggestions before I get ripped off and call the service people?