Hello Porkrhind,
Well if you have New Caldera Spa ...... Year Make Model ? It most likely has warranty on it ?
Try this,
Reset the spa and put it in summer mode.........This may help.
Set temp to 80*. Simultaneously press and hold for three seconds the temp up button and the temp down button to activate summer mode. You will see a sunny icon appear on your panel. This should be in your owners manual ? This will prevent heat transfer from the circ pump by turning it off for a set period of time during each day. The heat drift can over heat the spa water near the heater and sensor causing " -------" errors during hot summer months.
Short of this if it continues I would seek a tech to have a look at it. Other things can cause ------- errors. But it may be as simple as that.
Hope this helps.
oink oink !