When I moved into my house last fall the pool water was clear and blue. When we opened this year and began to shock, heavy iron stains appeared on my stairs and liner. I'm currently taking steps to get rid of them, but am wondering where they came from. The previous owner had a heater hooked up, which is now disconnected. I'm thinking the metals came from that because our fill water is city with no metals. Also, my pump is pretty rusty/corroded on the exterior of the metal portion. Water doesn't actually pass through that, does it? If so, I'm guessing that may be another source. Any thoughts? I plan on replacing my liner and water next season, and want to eliminate the source beforehand. Thanks.