I am building a new pool and looking for a spa heater. Basically I only want to heat the water in the spa and not the pool. Do you have energy efficient pumps that only heats the volume of water in the spa ? Something small. In the current plans since I had not planned for a pool heater - the plan only has a 2 speed pump. Since I want to heat the spa only do i need to install a separate pump for the spa and pool in addition to the spa heater. The spa is an 8ft radius 1/2 circle in size. Pool is 15x32 irregular size.