I am simple guy, I do not have SWCG, I use pool heater only to heat my external jacuzzi (I have in ground jacuzzi next to the pool with a waterfall to the pool from jacuzzi) - this is how it was when I bought the house. As there is no way to insulate jacuzzi and to heat it every evening in winter for 2 hours with 400 thousand BTU gas heater seemed to me a bit wastefull, I got older external jacuzzi, took out the 2 motors, put it next to the pool heater and pool pump and hooked it up to pool pump and pool heater and ti works like charm, keeps water warm and takes maybe 5-10 minutes to heat it every evening.