Distilled water with POR-15?

So I am about to derust my tank and I noticed that the instructions for the POR-15 doesn't say anything about using distilled water with the Marine Clean.
Wouldn't it work better with distilled water? It doesn't have the corrosive properties of tap water.

Wait for the big boys to answer that....but somehow the thought of worrying about how corrosive your tap water is...doesn't make too much sense to me when you are using a rust desolver to clean the tank...or?..... :wink: