In the past, pool owners wanting a more “eco-friendly” filter media with great filtering capacity would use a Diatomaceous Earth (DE) filter (more info about those here). But a growing trend of using glass as a filtering media is giving the DE filter a run for its money. Using glass in a filter isn’t really anything new, as it was used in slow filters in England as early as the late 1700’s and was the basis for several early patents.
Glass filter media is compatible with many water sanitization systems, including ozone, saline, UV, traditional chlorine and bromine systems as well biguanides and aqua catalyst mineral platforms. Glass is designed to be backwashed every 5th week, unlike typical DE or sand filters that require weekly backwashing. And because it requires fewer backwashes, you can reduce the amount of water you use, some technicians report as much as a 100,00 reduction per swimming season per pool (according to April 2012 Pool & Spa News). And if it’s important to you and the maintenance of your pool, it is possible to vacuum through the filter with this media.
Part of what make the glass a great filter media is that the surfaces of the glass pieces have a slightly negative charge which helps it to capture fine particles and hold them until backwashing. The glass grains made from bottle glass, as opposed to plate or window glass used in the past, are prove a fine particle separation, and since the grains are very angular they have a more open packing space and greater permeability than a standard sand filter. Glass grains are also more resistant to breakdown through backwash cycles and they don’t provide a toe-hold for bacteria to resist flushing during the backwash cycle because of their homogeneous shape.
Filters using glass media need a multiport valve instead of a slide valve, and require a pea gravel base (like most sand filters) above the laterals. Purging the entire filter bed depth, which is larger than the typical 6” depth of a sand filter, does require a different method than your standard sand filter so make sure your pool technician is aware of it and familiar with glass media. In residential pools, the estimated life of the glass media is about five years, but may require a bag to restore the bed depth after two or three years.
If a glass media filter has peaked your interest, give Premier Fiberglass a call and we’ll be glad to help you out.