Product review (4 stars): Good, but doesn't last long
I have a&nbsp;<a data-hook="product-link-linked" class="a-link-normal" href="/The-Sharper-Image-EV-HD10-Cool-Mist-Ultrasonic-1-Gallon-Humidifier-with-Clean-Mist-Technology/dp/B002RWJ9BA/ref=cm_cr_arp_d_rvw_txt?ie=UTF8">The Sharper Image EV-HD10 Cool Mist Ultrasonic 1-Gallon Humidifier with Clean Mist Technology</a>&nbsp;and this tablet really only lasts for one gallon. I haven't been totally convinced that it helped with white dust but it seems to have helped kill any musty bacterial growth, which is good enough for me.

It might prolong the life of the humidifier or decrease smells and mineral buildup, but it does not eliminate white dust. Don't buy it if your goal is to do that.