Carbon Pre Filter Water

There are two primary types of filter design: pleated and spun (or wound). The latter simply have the filter media wound or spun around a base, creating layer after layer of filtration. Pleated filters have their media folded into a series of pleats, dramatically increasing the surface area available for filtration, and allowing for smaller housing sizes. In addition to the greater surface area, pleated filters have a lower pressure drop, increasing the flow rate out of the filter. In general, a spun filter is best if particles of a variety of sizes are to be filtered, thanks to their irregular and complex design. A pleated filter works best to block uniformly sized particles, and offers greater consistency in doing so since it is much easier to manufacture a pleated filter's pores to a specific size.

The pores of a filter are measured in microns. "Micron" is another term for the micrometer, or one-millionth of a meter (0.000039"). Probably the easiest thing to use as a frame of reference at this tiny scale would be a human hair: one strand is typically around 90 microns wide. The lower the micron rating, the smaller the filter's openings. Lead particles range from 0.1 to 0.7 microns, bacteria between 0.3 to 60 microns, and sand at anywhere between 75-150 microns.

Filters can be made of several materials; those that we offer are made of cellulose, polyester, polypropylene, or carbon. Cellulose filters are often the least expensive kind, and are derived from the very same cellulose that makes up the cell walls of plants and trees. Because of this organic component, these filters can be especially prone to bacterial infestations and "biofilm", where groups of microorganisms adhere to each other on the surface. This is why cellulose filters are not be used for untreated water, like that coming from a well. Cellulose filters will deteriorate if kept in a filter canister for too long which can cause the disintegrated particles to flow into your piping, leading to clogged aerators. Cellulose filters should be replaced after 3 months of continual use to prevent this type of disintegration and of course consumer aggravation.

Polyester and polypropylene are synthetic materials that are much more bacteria-resistant than cellulose. As such, they are a good option for untreated water supplies. These filters can be pleated or spun, and some can even be cleaned and reused for certain applications. With cellulose, polyester and polypropylene, it is mechanical filtration (filter physically traps particles) that does the work. As such, pay careful attention to the micron rating of these filters and the contaminants in your water, as that will be the sole determinant of the filter's success.

Like the above materials, carbon filters not only provide mechanical filtration, but also have unique benefits that make them especially effective. Carbon is the go-to medium for taste and odor removal, and is particularly good at removing chlorine. Chlorine is used as a disinfectant in most municipal water supplies, and although the concentrations are monitored to be safe for consumption, there can be bothersome residual effects like odor and taste in your water, and drying-out of skin and hair. Chlorine also introduces Disinfection By-Products (DBPs), some of which can be harmful and even carcinogenic.

Chlorine molecules adhere to the filter surface (a phenomenon called adsorption), as do most DBPs. Adsorption provides greater efficiency than straight mechanical filtration, but once the carbon has been saturated, there is no possibility for re-use. And it's not just adsorption at work: some of the chlorine will be chemically reduced by the carbon, resulting in chloride, which presents problems only at high concentrations (and is easily removed by reverse osmosis).

In addition to chlorine, carbon can also be used to remove chloramine (another disinfectant used in municipal water supplies), but this requires significantly longer contact time between the water and carbon, as well as more carbon, to be successful. With carbon filters, the slower the flow rate, the more contact time contaminants have to diffuse and be adsorbed while inside the filter, so a faster flow is not necessarily best.

One of the major radioactive isotopes produced by nuclear fission, Iodine-131, can be removed with activated carbon (manufactured to have smaller pores), and most Giardia parasites are filtered out at 1 micron or less. Many of the Volatile Organic Compounds (VOCs), agricultural chemicals, and heavy metals regulated by the EPA can be addressed with activated carbon.

If you're having a problem with iron and rust, pour a glass of water and let it sit for 15-20 minutes. If nothing settles at the bottom, the particles are too fine and a filter will not help (you'll need to look into iron removal or a water softener). If particles do settle in the glass, however, a filter of 5 microns or less should take care of the problem.