My 35000 gal salt water rectangular pool and attached spa -8x8ft are currently heated by a heat pump for the pool and gas heater for spa. The equipment was purchased in 2005. Natural gas spa heater just failed. I need advice on best heating strategy regarding equipment. One gas heater for both? Stay with heat pump for pool and gas for spa? Spa is on same filter pump as pool but separate plumbing circuit. If gas heat alone is the way to go, is there a brand preference? How would you set it up? I have the iAqualink control system and a Jandy controls. Aqua pure salt system. What equipment brand would you recommend?