Fluval makes a peat moss extract that you can put into your filter. I use it in my canister and my HOB filter. I live in the country and have hard water as well. It's not a fix all but it does bring it down some.
I have one box's worth in a mesh bag in my canister filter for my 120 and I have about 1/4 of a box worth in a mesh bag that I dropped in my HOB filter for my 29. You have to change it every 2-3 months. Again, it's not a fix all but it does help some.