Check the listing for details. Tube and Shell Heat Exchanger 400kBtu 304 Stainless Steel For Spa Heat Recovery. Condition: New. Listed at 172.70 USD. Product description: ★The pool heat exchanger is made of high-grade anti-corrosion stainless steel, which has the characteristics of anti-rust and salt water resistance, so it is very durable and very suitable for chlorine or salt pools and spas. 2 inch FPT is used for swimming pool water, and 1 inch FPT is used for hot water. ★The salt pond heat exchanger adopts an innovative in-line design to ensure a continuous constant temperature and indirectly transfer heat between any hot water circuit, steam circuit and any swimming pool or spa facility. ★The shell-and-tube heat exchanger is based on the 60°C (140°F) temperature difference between the inlet and hot water, and can provide a fresh pond of 400 kBtu/hr. It gets hot immediately without waiting.