As we know, well water can be packed with iron. If you are unable to have fresh water trucked-in, or it's just not practical, pre-filtering is a common practice. Whether you chose to do it through your water softener or manually through another DIY product (i.e microfiber-filled bucket, etc), the more iron you remove before the water hits the pool the better. If you do some searching here on the forum, you'll find plenty of discussions of folks who created some very good filters at home. Of course don't forget a regular supply of sequestrant once you're done filtering to help contain the iron that did get in the pool to keep it from staining.