Rockin Green soap is the only cloth diaper friendly detergent that I know of that has a specific solution for hard water. We live rurally and have hard water, so this would be really nice to try out. The Classic formula works well, but I do feel like I use "too much" for each load. The Hard Rock formula is 'made for us'!
Visit My Silly Monkeys for the Rock Green Soap Hard Rock giveaway: