Yuck! Lots of rusty water in sump pit

Hoping someone had this issue, and can shed some light.  I have a iron sump pit, with a pump that spits out rusty water to the outside.  where there is a concrete driveway, and it gets stained easily.  I tried flushing the whole system with Rust out and lots of water, but i still have rusty water coming out.  Temporary i extended the pipe with a extension so it lands on grass, but it then blocks parking to side of house.  Someone mention it could be iron bacteria, and to try lemon or chlorine.  Before i do any of that, if anyone has any suggestions please let me know.