Since controlling my own chemistry, this has to be the best year I've had with my pool in 8.5 years of homeownership. I've noticed two brown stains on the bottom of the pool, they clearly look like iron stains (about the size of a quarter each). They are on the transition between the shallow and deep end. There isn't wide spread staining on the pool, and it was filled with municipal water. I'm thinking they were caused by Irma throwing something metallic (nail, screw, etc) in the pool and our cleaner eventually got it out. I am planning on jumping in with a few vitamin C tablets and removing them before using metal sequesterant. Any thoughts?