hard water, solotion?

So I was getting readt to re-order hottub filters and decided to browse the site to see if by chance they had any bulk pack deals or anything else I couldn't live without, and well maybe I found one. What do you all know/think about these products:
http://www.ecogeeks.com/greenstore/inde ... cts_id=204
http://www.spadepot.com/shop/Pre-Fresh- ... 4C635.aspx
I have a well, and very hard water. I use a softner for the house, and that helps a great deal, but I still can't wash a car, even the mr clean 'sample' filter turned brown after 1 wash and still left spots. Would this allow me to fill my hot tub, and wash a car?

(I like flashy, fancy webites, I can fall for lots of things easily, but I try to refrain from wasting too much money!)