The humidifier

The humidifier is the piece inside the box that holds water, or a solution, and lets it out slowly. The hygrometer only reads the air. It does not add moisture. If the element is dry, hard, or moldy, the number on the dial will not come back up no matter how often you look at it.

Distilled water

Use distilled water. Tap water leaves minerals and chlorine in the element, and the element clogs. A few drops, or a short soak, until the foam or the crystals are damp. Squeeze or wipe off the excess so it does not drip onto the cigars. Standing water in the tray is too much. Put the element back with its vents clear of the cigars.

Between full recharges, distilled water is enough to top it up when the reading falls toward the low end of the range. How low is too low, and when to open the lid instead, is on Care.

A two-way solution

Some elements are charged with a solution of propylene glycol and distilled water, often sold for this job. That solution both gives off moisture and takes excess moisture back, and it slows mold. It is not the same as pouring more water in.

How often you recharge depends on the room: every month or two in a dry climate, less often in a humid one. When you do recharge, rinse the element with distilled water and let it dry so the old solution does not stay behind, then add the new charge the way the element’s own note says. Do not mix a homemade percentage if the element came with a fill line and a bottle. Follow that, and skip tap water either way.

When to replace it

An element that has gone stiff, or that shows mold, gets replaced. Washing mold into the rest of the box is worse than buying a new element. A humidity pack, the sealed pouch you drop in and throw away when it turns firm, is the other common choice. It does not get refilled with water. You replace the pack. Either one can hold a seasoned box. The pack is also what a travel case usually uses. That case is on Travel humidors.