I've got a 5gal. that my mom got me in march, and right now i've got a dalmation mollie, a silver mollie, 2 long-finned danio's, a cory cat, and a baby guppy that my mom's mama guppy had in there and i haven't moved yet. anyway, i live in an area of town where we have hard water, all the water is hard in this town, and i was wondering how i could bring it down? i don't know the number it's at or what that's called, but my fish are all fine and healthy, happily swimming around actively all the time. any advice would be appreciated.