Product review (3 stars): Made from caustic chemicals, will not re-buy
I purchased this product with the Essick Air MA0800 humidifier and made the mistake of using it without fully reading the directions.  Basically, I read quickly  that it required a cap full for a gallon of water and that if it gets on your skin, it should be washed off.  It is impossible to fill a cap full, and then pour that cap into the water bottle, without spilling it on your hand.  I immediately splashed it on my hand and rinsed my hand off in the bathtub faucet as I was filling the rest of the bottle.  I later realized that my thumb has turned white with damaged, dry skin.  On spending more time with the directions, I read that the chemicals are caustic, cause irreversible eye damage and should only be used with googles or face shield and gloves.  I've already caught my cats drinking out of the water reservoir of the humidifier while I was filling the bottle (fortunately, before I added any chemicals) and can't see how to keep them from drinking the next time I fill the humidifier bottle.  As I'm adding the chemical to water, the risk of chemicals splashing seems too high...and I'm not about to buy goggles to keep my humidifier mold free.  Unfortunately, I'm going to have to search for a safer product for myself and my cats.