I have a 2008 Bullfrog 331 (only 205 gals.) and live in Reno, NV. Since this spring it has been running between 106 and 109 degrees even though I have it set at 101. It was installed in December 2007 and through the winter it seemed to run at the set temp. The local dealer has been here several times, mostly just looking at it but has replaced the temp. sensing unit. They have told me that the 'extra' heat is coming from the pump and motor which is normal due to the filter cycle time that I have it set at. I have had it set at the factory setting which is 4 hours, twice a day for a total of 8 hours. I use my spa almost every day for 5-10 minutes rarely turning the jets on. The dealer's solution was to reduce the time it filters (and ozonates) to 1 hour, twice a day. That has reduced the temp. to what it is set at. However, what was new water 30 days ago with this new schedule is now 'skanky' and needs to be changed. I have owned 6 spas in the last 18 years and have always changed the water between every 60-90 days. I feel 2 hours a day isn't enough time to filter/sanitize the water.
My question(s) is this- does anybody have this problem and with this spa? Is the dealer blowing smoke up my butt? Any suggestions? Thanks in advance. Jim

I don't think they're blowing smoke. Warm/hot exterior temps with longer filter cycles will increase water temperature due to the friction of the water going through the pump. So reducing the filter cycle lowered your temp. Can you switch the spa to thermistat mode? Only then circulates when calling for heat? Maybe during your season when you can't run it 8 hours a day you'll need to add more sanitizer (Chlorine/Bromine). That would relieve the skank.