Just Purchased a new hot springs rythm. after a day it was at 102, which I had set it too. however after using it for 30 minutes, it won’t maintain a temp over 98 degrees - usually around 97. it was pretty cold out, 25, but we’ve never had this issue in the past. any suggestions? The lcd doesn’t display is the heater is on or off, so I’m not sure when it’s actually heating.