Someone posted on the forum a while ago that had very high iron in his well water. I don't have time not to search for it - but you can look through old posts. They said every year they add a strong flocculant and after it circulates they turn off the filter and let it sit for 48 hours. Then they vacuum all the stuff that falls out on the bottom to waste. I will try to find it when I have more time, I am off to a graduation. If someone else remembers the post or wrote the post please let us know.