The University of Arizona recommends replacing swamp cooler pads rather than attempting to clean them. Aspen wood pads are a good choice for most swamp coolers. To extend the life of pads that are intact, owners should reverse them, allowing the water to flow in the opposite direction, provided they are in otherwise good condition.
H2Ouse recommends installing new cooling pads at the beginning of the cooling season. Midway through the season the owner should check them again. Pads that show a great deal of mineral buildup require replacement. In most locations, a set of Aspen pads provides adequate cooling for the entire season.
Some manufacturers recommend regular use of treatment tablets in the water. These tablets freshen the air, reduce mineral buildup and decrease corrosion. By reducing mineral buildup, they extend the life of the pad.
Regular replacement of pads prevents buildup of scale and corrosion of the metal parts of the swamp cooler. According to H2Ouse, hard water requires more frequent replacement of pads and reduces the life of the swamp cooler by 50 percent. Some manufacturers attempt to overcome the issues of hard water using bleed valves to drain a portion of the water in the reservoir. Other options include softening the water to increase pad and cooler life.