Sounds like your circ pump is shot. You may be able to get it going again temporarily, but it is not going to last.

Sorry to be a pest but I wanted to make sure of my situation before I invest in a new circ. pump...I already bought the thermisters which I don't think I needed so I want to be sure...After running the bengal for a few days (circ. pump OK) I then use the spa (green and red light on) after a while the green light goes out, which I assume is normal given the temp. drop while using...After I turn it off the circ. pump doesn't restart...I leave it alone for a day or so and then toggle the GFI outlet and I can get it to restart and start the process all over again...Is replacing the pump the only solution??? I still haven't heard back on which is the discharge end of the pump so I can see if an air bubble is causing the problem...but I've read that if the circ. pump runs for 20 mins. or more than there's no bubble...Thanks again for putting up with me...Jym

Is this tub running on 220 Volts?

If so, as Hottub.Pool_Boy said, your filter may be too dirty. If it runs fine when you are not using the tub, the circ pump may be getting enough water through the filter to let the heater heat. However, when you turn the jet pump on, the jet pump and the circ pump/heater both need enough water to work properly. If the filter is dirty and the tub is 220volts, when the jet pump is turned on, it may not be allowing enough water into the circ pump which would cause the heater to get too hot quite fast and cause the lights to flash.

Take the filter out and let it run for a few days and see what happens.

Thanks for the reply Dan...My spa is 110v...I've left the filter out for three days with the circ. pump running...but it won't restart after running the jets unless I leave it off for a day when I toggle the GFI breaker repeatedly until it kicks in...Sorry to sound like a broken record on this but the pump has only been in the spa since January, I called the company where I bought it but although I put it in in January I bought it over a year ago so no warranty...Thanks again for all your help.... Jym

Thanks again to all that helped me...I ordered a new circ. pump and filter...took out the old (newly cleaned) filter and replaced it with the new one before I replaced the pump...Voila!!! the old circ. pump has been working for the last week and a half with no problems...I guess the old filter just couldn't be cleaned even though I cleaned it only one time previously...What did I do wrong with the old filter??? I cleaned it only when I could tell the jets were weaker...I usually left the filter in the cleanser for about a week then hosed it off...Is this the right method??? Thanks again, jym