I left for a few days and had the pool green up on me so I decided to get the chlorine automated. I really like the idea of a SWG since I won't have to worry about dragging chlorine around. I read about rust concerns in SW pool and the only thing I can see that's stainless is the lights and screws in the pool. BUt more importantly the water heater. How do I know if my water heater can handle the salt?