Product review (5 stars): Very easy to install
We considered using RO filtered water or even distilled water, but this turns out to be by far the easiest and most economical way to purify the water we're using in our Air-o-Swiss humidifier (which we just love!).  The original one that came with the humidifier lasted a lot longer than we expected - two months of nightly use - so we're glad we didn't choose to lug a bunch of water jugs of distilled water.  We just fill up the tank once every two nights at the faucet and we're set.  We haven't see any issues with white dust from the minerals in the water, and we have hard city water.