By Marcelle Dibrell

The pool filter is the hardest working piece of equipment on a swimming pool, capable of removing the contaminants that make swimming pools not just uninviting, but unhygienic and dangerous.

And basic water filtration has been around for thousands of years because humans have likely always believed that water purity was important, as determined by its appearance, taste, and odor.

Indeed, methods for water filtration can be traced to the earliest recorded history. Sanskrit medical texts advised filtering water through sand in approximately 2,000 BC.

But the first domestic water filter wasn’t invented until the 3rd century BC, when Hippocrates, the Father of Medicine, introduced the “Hippocratic Sleeve.” It was a simple cloth bag through which water could be poured after being boiled.

The first documented use of modern-day sand filters dates to 1804, when John Gibb, the owner of a bleachery in Scotland, installed an experimental filter and sold his surplus to the public.

Using sand for water filtration became refined by private water companies in London in the decades that followed as filtered water was supplied to every resident in the area.

The practice of filtering water for sanitation in western civilization only began to be taken very seriously, however, after a series of epidemics (cholera in 1854 and typhoid fever in 1856) caused scientists to wonder if contaminated water might be responsible for spreading the diseases. Physician John Snow demonstrated that contaminated water was the source of the outbreak, which led to the Metropolis Water Act. It was the first time that water supply companies were regulated, and it set water quality standards that involved filtration.

Sand filtration has been in use for thousands of years, but our modern methods of water filtration remain a relatively recent development.

Within swimming pools and spas, the current most prevalent forms of filtration also include DE (Diatomaceous Earth) and cartridge filtration, and these were only first implemented in the 20th century.

It has long been reported that DE was first used in Hollywood swimming pools during filming Esther Williams’ aqua musicals in the 1930s.

During filming, it is said, the pool water continuously needed to be replaced due to cloudiness. So local engineers selected DE as the ideal media to keep the water clear for filming.

However, Williams’s first bathing beauty movie didn’t come out until 1944, so at least, the dates cannot be correct. In fact, DE for water purification is commonly attributed to have been developed by the U.S. Army Engineer Research and Development Laboratories who were looking for a new type of water filter suitable for rapid mobile military operations during the Second World War. However, it had been used for water purification as early as 1892 during a cholera epidemic in Hamburg, Germany, after Wilhelm Berkefeld recognized the ability of diatomaceous earth to filter water and invented Berkefeld filters.

Sometime during or after the war, DE filtration was applied to swimming pool water, perhaps because it was popularized by Hollywood, and became the dominant filtration method, especially in Southern California pools, where it is still widely used today.

DE use was still in its infancy in 1956, when Dick Meissner began manufacturing DE filter bags for Anthony Pools. They were called the Anthony McIntosh filter bag, and they were the first products made by Unicel, with Meissner its president and founder.

Meanwhile, cartridge filtration only emerged as a viable pool medium following Dupont’s invention of Reemay, a new non-woven but rather spun-bonded 100-percent polyester material.

Early efforts at cartridge filtration were made with a paper-type material that did not hold up well in swimming pool applications.

Meissner recognized the potential of this new medium and in 1964, the company came out with the first cartridge element made of Reemay, which is still widely used in today’s cartridge filters.

In the decades that have followed, many advancements and new technologies have emerged for swimming pool filtration.

For example, recently, Pleatco has introduced a new patent-pending Advanced Point Bonded Filtration Fabric for cartridge filtration.

Sand and DE alternatives also abound.

In this special issue of Service Industry News, we’ll take a closer look at some of these pool and spa filter options.