I live in the same area as you in CT and my recently purchased Sundance tub was consuming 12 KW a day at 100F, used daily , 350 gallons. I noticed a ton of heat loss from around the control panel side of the tub and pumps. I insulated that area and found my usage is now down below 10KW a day.
Your usage is over 2.5 times what mine is. I don't know how
The pictures attached are before and after insulating. I have a thermometer mounted inside the spa at the control panel and the temperature is 76F in the cabinet. That heat was just escaping to the outdoors through the uninsulated outer panels. I did not have insulation to do all four sides but I plan to.