No, I don't have this problem, and at the risk of butting in where I'm not wanted, I'm going to anyway.
To reduce the minerals/hardness of the water it needs to be softened in some manner. If the water can't go through a water softener, or reverse osmosis (in which case electrolytes, etc. would have to be put back into the water, one thing you could try is to add some peat to the filter. Don't know/can't remember what kind of filter you have, but I've read that both Hagen and Eheim both sell peat for their filters.
Aquarium Pharmaceuticals also sells a water softening pillow, which is not cheap to use on a continual basis and I've read isn't effective in large tanks. I think an other member uses it, however, and has made positive comments about it.
"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-
