FAQ - Activated Carbon Filtration
What is Activated Carbon?
Carbon is an extremely porous material that attracts and holds a wide range of harmful contaminants. Activated carbon is carbon which has a slight electro-positive charge added to it, making it even more attractive to chemicals and impurities. As the water passes over the positively charged carbon surface, the negative ions of the contaminants are drawn to the surface of the carbon granules.
What forms does it come in?
Activated carbon filters used for home water treatment typically contain either granular activated carbon (GAC) or powdered block carbon (carbon block).
Which is generally better, GAC or carbon block?
Although both are effective, carbon block filters generally have a higher contaminant removal ratio and are more resistant to channeling.
Are all carbon filters equally effective?
No. Activated carbon filters are usually rated by the size of particles they are able to remove, measured in microns, and generally range from 20 microns (least effective) down to 0.5 microns (most effective). The two most important factors affecting the efficiency of activated carbon filtration are the amount of activated carbon in the unit and the amount of time the contaminant spends in contact with it. The more carbon the better. Particle size also affects contaminant removal rates. The most common carbon types used in water filtration are bituminous, wood, and coconut shell carbons. While the coconut shell carbon typically costs 20% more, it is by far the best of the three for most water filtration situations.
Can I use taste and flow rate to determine when to change the filter?
No. These are very poor methods of monitoring your water filter for maintenance. Once the bad tastes have returned, it is already far too late - contaminants have passed through the filter and into your drinking water. A carbon cartridge may be able to control taste and odors long after the carbon has lost its ability to effectively reduce other toxic contaminants. You should always follow the manufacturer's filter replacement schedule to ensure optimal filtration.
What is Backwashing and do you recommend it?
Backwashing is the process of forcing water through a filter in the wrong direction to unclog the dirt and sediment which has blocked the filter. Backwashing is a common practice for certain whole house and commercial units which are treating large volumes of water for utility purposes but it is not a recognized practice for small point-of-use drinking water systems.
Do you sell silver-impregnated carbon filters?
No. Most research suggests that silver impregnated carbon filters have a very short-lived effectiveness in preventing bacteria growth in a water filter system. There is greater risk that unhealthy levels of silver ions will be passed into your drinking water than from potential bacteria build-up in your carbon filter if proper maintenance of your system is followed.