You add fluid, weather you choose to use a glycol mix, or distilled water( which is the only chemical and bacteria free water you should ever use) by taking a butter knife and barely insirting it through the openings closest to one side and gently prying the top open. Be careful and open each slot till the top pops off. The top has a series of small tabs that snap in a series of small groves. Proceed to fill your base 3/4 of the way up. Now just give the crystals time to absorb the fluid to revitalize themselves. After the fluid is absorbed simply snap the top back into the groves. As for your discolored crystals you can remove them before replacing the top. There are replacement crystals available from a few different sources. They are sold in a small bag which can refill many humidifiers.
Dave in Largo,Florida June 26, 2012
"Work well, but limited lifetime"
I bought 4 of these guys when they were on sale on www.CigarMonster.com, they work well, just add some distilled water and put them in your box.
They are somewhat hard to get water into, since you have to pour it onto the top of the box, through the slats. If it does not drain in, push it with your finger, and then it will usually start to run in.
Let it sit for a few minutes, then shake out the extra water. I would not mount upside down.
I have had them just under a year, and one of them is starting to turn on me. The plastic crystal's inside dry up eventually. Also the one has the crystal turning brown, so it does not look that good.
Other than that, the work well for the price. But realize they are not for a lifetime, unless you plan to only live 12 months.
TimtheRockstar in Austin, Texas November 14, 2011