Essick Air 1970-2 Humidifier, 2-Quart Bacteriostatic Treatment, 2 Pack

Why I keep a bacteriostatic on the shelf

After a few winters of babysitting evaporative humidifiers—scrubbing slime, chasing musty odors, and swapping clogged wicks more often than I’d like—I started adding a bacteriostatic treatment to every refill. The Essick bacteriostatic treatment has been my go-to for a couple of seasons now, and it’s made routine maintenance far less tedious. It doesn’t transform a humidifier into a zero-maintenance appliance, but it does exactly what it claims: it slows biological growth in the reservoir and on the wick, which is where most smells and slime start.

What it is—and what it isn’t

This is a clear, water-like additive packaged as a 2-pack of 32-ounce bottles. It’s designed for evaporative (cool-wick) humidifiers—the kind with a wick filter and a fan. The goal is simple: inhibit bacterial growth in the tank and on the wick so you get cleaner output, fewer odors, and a longer interval between deep cleans.

It’s not a descaler, softener, or “white dust” fix. If your issue is mineral residue from hard water, this won’t solve it—use distilled water or a mineral cartridge for that. And it’s not a fragrance or deodorizer; it isn’t meant to mask smells, it’s meant to prevent them by controlling what causes them.

Setup and dosing

Using the Essick treatment is straightforward once you establish your per-fill routine. The bottle provides a per-gallon dosage. Because console humidifiers can hold several gallons across one or more tanks, I measure the tank capacity once, then note the number of measures per refill on a piece of tape on the tank. A small dedicated measuring spoon or a squeeze-dosing bottle makes this easier and avoids guesswork.

A few practical tips that helped:

• Pre-measure for your exact tank size. If your tank is 1.5 gallons, don’t round up—overdosing can increase odor and doesn’t improve performance.
• Add the treatment after you’ve added most of the water, give the tank a quick swirl, then top off. It mixes readily, but this avoids pooling.
• Keep it off surfaces and your hands. Wipe any drips and wash up after refilling.

One thing I’d change: the label is dense on cautions (as it should be), but light on dosing shortcuts for non-integer tank sizes. A marked cap or measuring chamber would make this more foolproof.

Performance in daily use

In evaporative units, the biggest benefits show up in three areas:

• Odor control: The classic “swampy” smell that creeps in after a few days simply doesn’t show up when I dose correctly. If I skip a refill or two, the smell returns—so the cause-and-effect is obvious.
• Cleaner tanks and wicks: Biofilm buildup is noticeably reduced. I still clean weekly (quick rinse and wipe) and do a deeper descale periodically, but the slime layer that used to appear on tank walls and wick frames takes much longer to form.
• Steadier performance: The fan no longer has to push through a musty, gunked-up wick after just a few days. Humidity output stays more consistent between filter changes.

I’ve run the treatment with small tabletop wicking units and a large console humidifier that holds several gallons. In both cases, it scaled well; I just adjusted the dose per tank volume. Over a winter season, I used less than a bottle per device with daily operation.

Scent and sensitivity

The treatment itself has a mild chemical/medicinal smell when you’re pouring it. In the air, properly dosed, I don’t notice a lingering scent in rooms with normal airflow. That said, if you’re incredibly scent-sensitive or you operate the humidifier in a small, closed bedroom at high output, you might pick up a hint of it—especially if you’ve overdosed even slightly. If that happens:

• Recheck your dosage per gallon (don’t round up).
• Increase ventilation or lower the fan speed overnight.
• Do a quick rinse of the tank and refill correctly.

If you still notice it, you may be better served by distilled water and more frequent manual cleaning, skipping additives altogether.

Compatibility and safety

• Best for: Evaporative/wick-style humidifiers (often branded as “cool mist” with a replaceable wick filter and a fan).
• Not for: Ultrasonic units that atomize water. Additives can be aerosolized and more noticeable in the room, and manufacturers often advise against chemicals in ultrasonics.
• Also typically unnecessary for: Steam (boiling) humidifiers, where heat controls microbial growth in the tank.

The bottle carries the standard chemical safety warnings. Treat it with the same respect you would a household cleaner: store out of reach of children and pets, avoid contact with eyes and skin, and don’t mix with other tank additives (bleach, fragrance drops, essential oils). Clear is a nice touch—it won’t stain tanks or wicks.

Maintenance impact

Even with a bacteriostat, you still need to:

• Rinse tanks weekly and do a mild descale as needed if you have hard water.
• Replace wicks per the manufacturer’s guidance; expect longer intervals than untreated water, but not infinite life.
• Empty tanks if the unit will sit unused for more than a day or two.

In my routine, the treatment cut “full scrubs” from weekly to every few weeks during continuous running. That’s a meaningful quality-of-life improvement.

Cost and longevity

The two 32-ounce bottles go a surprisingly long way. Because the per-gallon dose is small, I can run a large console unit daily through an entire heating season on roughly one bottle, and a smaller tabletop unit on a fraction of a bottle. On a per-day basis, the cost is low—especially if you factor in fewer wick replacements and less time spent cleaning.

What I like

• Effective odor and slime control when dosed correctly.
• Clear formula that doesn’t stain tanks or wicks.
• Works predictably across different evaporative models and tank sizes.
• Low per-use cost; a 2-pack easily covers a season or more for most households.

What could be better

• Measuring could be more foolproof; a marked cap or built-in dosing chamber would help.
• Sensitive noses may catch a faint chemical note if overdosed or used in tight rooms with little ventilation.
• Labeling could more clearly emphasize “evaporative only” to head off misuse in ultrasonic units.

Practical dosing workflow I recommend

• Label your tank with exact capacity and the corresponding dose.
• Keep a dedicated 1-teaspoon (or milliliter-marked) measure next to your refill station.
• Rinse and wipe tanks weekly; descale separately as needed—don’t rely on a bacteriostat to tackle minerals.
• If you’re troubleshooting persistent odor, replace the wick; biofilm inside an old wick can overpower any treatment.

The bottom line

The Essick bacteriostatic treatment has earned a permanent spot in my humidifier kit. It doesn’t eliminate the need for cleaning, but it meaningfully extends the time between scrubs, keeps reservoirs clearer, and, most importantly, prevents that telltale musty smell that signals microbial growth. Used as directed in evaporative humidifiers, it’s a simple, inexpensive step that pays off in cleaner operation and steadier performance.

Recommendation: I recommend it for anyone running a wick-style evaporative humidifier through the heating season. It’s effective, economical, and easy to integrate into a refill routine. Skip it for ultrasonic or steam units, and if you’re highly sensitive to chemical scents, start with careful, exact dosing and good room ventilation to see if it fits your comfort level.