Can anyone give me suggestions on ILOC problems. Bought the house used and was told that hot tub had problems. I have replugged circuit board connectors and tightened electrical screw connections. After about 2 minutes of heating, the display says ILOC which I believe means intermittent loss of connection or contact. Turning power on and off resets it to operational until the next ILOC after 2 minutes. Bubbles can be seen when unscrewing and removing the the Crystal Pure filter cover so it looks like the heater water is circulating. If I lower the control panel temp below the actual water temp I can run the jets without getting the ILOC error.

I believe ILOC means INTERLOCK.
I think this error indicates the controller detected tampering with the temperature probe.
To prevent people from making the spa hotter than is "safe" the interlock system trys to detect people monkeying with the temperature sensor.
This error also happens when the temperature probe is failing.
You might try reseating the temperature probe connection.