Coates 12418PHS-CN Single Phase Commercial Electric Heater 240V 18kW - The Coates model PHS-CN heater is designed for use in pools and spas that use chlorine generators as their sanitizing system. The heater’s copper-nickel tank and titanium heating element offers increased corrosion resistance in pool and spa water with a maximum salt concentration of up to 3500ppm. It has element, flow and high temp "on" lights.