Yep, we have the Nature2 in the filter closest to the control panel which they said is the one the circ pump goes through. So far the spa is awesome! We're in it 5 nites out of 7 for generally 30 - 40 minutes at a time. Sometimes not even with the pumps on the whole time, just sitting in the 102 water is nice. The other nite it was well into the single digits and we were out there. It's about 15' from the house to the tub and the coming in isn't bad since we're warmed up, it's the run out to jump in the tub that's testy
I think I'll take it to a 12 hour cycle and see how that does, might even do the 3 hours - 4 times / day setting. If the water still is crystal clear and is balanced ok, I'll take it down to 8.
thanks for the advice!