Swimming pools are the perfect distraction on a hot summer day, but most people rarely think of the intricate processes that keep them clean. A pool without a proper sanitation system is unsafe for human enjoyment; pumps and filters are necessary for maintaining bacteria levels in the water.
An unclean pool can house numerous micro-organisms from infected swimmers and, left untreated, can spread hazardous diseases. Swimming in contaminated pools can cause diarrhea / Giardia, eye and skin infections and even respiratory problems if the water is swallowed.
To most of us, a pool is just a big hole in the ground filled with water-but they're on pool accessories like water pumps, which utilize complex processes to keep water clean. During the dumping process, an electric motor runs an impeller which draws the water from the drains and through a strainer-which removes large debris from the water. Next, the pump moves the water through a filter before returning it to the pool. State law requires that all the water must be processed within a amount of certain time-usually between 30 minutes and 6 hours, depending on the size of the pool. To illustrate the vital role that pumps have in a pool system, imagine a typical apartment-size pool: 167,000 must be treated (pumped, filtered, returned) every six hours to keep the water sanitary!
Filters are also important pool accessories because they catch microscopic debris that passes through the strainer. There are three types of filters: sand, cartridge, and diatomaceous earth (DE) filters.
Sand filters are the most common because they are the most affordable. In these filters, water passes through tanks made of concrete or fiberglass which contain a layer of special grade sand. Gravity pulls the water through the tanks and the sand layer collect small debris before the water is returned to the pool. However, dirt and debris collect and build up over time-so slowing the flow of water in the pump. When a custodian discerns that there is a blockage, they can reverse the flow of water (backwash) and redirect it into the sewer.
A diatomaceous earth filter is comprised of powder made from fossilized residues of sea organisms. When covered on a grid, these organisms act as little sieves that are efficient at catching microscopic particles. To recharge these filters, owners just pour more DE powder into the skimmers.
Cartridge filters use thin paper or cloth as a medium. These filters need to be replaced every 8 years or so.
Cleaning chemicals (like chlorine) are important pool accessories, but it's important to consult a professional on how much a pool needs. An overabundance of chemicals can be irritating to swimmers' skin and eyes.