Products for Maintaining Your Evaporative Swamp Cooler

Swamp cooler side panels
Aaron Stickley

Proper maintenance is critical to keeping your evaporative cooler working efficiently, with fewer repairs. There are a number of products you should know about to help you in this goal. 

Tired of changing cooler pads halfway through the season? Depending on how hard your water is, the mineral and scale build-up in the swamp cooler might be extreme. The more scale build-up on your cooler pads, the worse your evaporative cooler works. Other concerns include keeping the water in your cooler fresh in order to avoid that "muggy" smell.  Here are some of the products that can help.

D-Scale and Evaporative Cooler Cleaner

When an evaporative cooler gets mineral and scale build-up, it might be time to use a cleaner or some form of de-scaler. This will help the cooler pads last longer. Also, clean pads can help keep the air temperature cooler, because more water can be absorbed into the pads and subsequently evaporated (it is the evaporation of water that gives the appliance the ability to cool air). For most cleaner products, you pour a certain amount of cleaner into the evaporative cooler pan with the water and run on pump mode for about 20 minutes. The scale and minerals will get washed out into the pan for you to drain out. Then, you drain the water, flush it out and refill the pan with clean water.

Purge Pump

Do you want to keep the water in your evaporative cooler clean all summer long? Try installing a purge pump. This will clean the water in the cooler automatically every 8 hours or so by pumping a percentage of the water out of the pan. Purge pumps are easy to hook up since they just plug into the existing cooler pump. Keep your water and the air fresh by having the old water pumped out and clean water coming in to be absorbed and evaporated through the pads. The discarded water can be used to irrigate a nearby garden, plants or trees if you want to avoid wasting water.

Water Filter

Filter incoming water with an inline filter. Preventing scale build-up is much easier than removing hard water deposits. So how about a nice in-line filter that will filter the water coming into your cooler before it gets pumped through the pad? This can reduce scale and lime deposits, leading to longer lasting pads. Inline filters can be installed anywhere on the water lines before the water goes into the evaporative cooler. If you have really hard water in your area, this type of filter can help prevent extra build-up on your evaporative cooler and pads.

Zinc Anode Rod

Keep the musty smell in your cooler from building up with a zinc anode rod. These are great for controlling rust, mold, and mildew in an evaporative cooler. When coolers begin to small, it's often due to bacteria, algae, and mold growing inside. Water, warm days, and stagnant water are a perfect mold breeding ground. Control this by adding a zinc anode rod, which inhibits the bad stuff from growing. Keeping growth under control will help keep your air quality safe and the cool air smelling fresher.


Drop-in tablets are another way to help prevent mineral and scale build-up. These are time-released tablets that you can drop into the cooler pan. They serve the same purpose as a cooler cleaner, but with these, you simply leave them in the cooler; the tablets contained pre-measured amounts of chemical and require no measuring. If your evaporative coolers pads are already clean, you might consider this as a good combination with a purge pump to maintain better water quality with little or no buildup.

NOTE: Don’t forget to winterize your cooler to help keep it in good shape. Even if you live in a warmer climate where freezing is not an issue, you can prevent some wear and tear to an evaporative cooler by putting it to sleep each winter.