Granular Activated Carbon Filter System & Clack 990 In and Out Valve Head

How Granular Activated Carbon Works

A granular activated carbon filter system uses granular activated carbon media to adsorb and remove contaminants from water, especially chlorine and organic pollutants. For specific equipment options, homeowners can review granular activated carbon water filtration systems. The following contaminants can be reduced or removed by GAC systems:

• Chlorine (taste and odor)

• Chloramines (with catalytic carbon media, as different carbon types are optimized for different contaminants)

• Hydrogen sulfide

• Many organic contaminants

• Pesticides

• Herbicides

• Industrial solvents

• Other chemicals, odors, and tastes

GAC filters are generally ineffective for removing heavy metals and microorganisms. They are also less effective at removing dissolved inorganic contaminants, so understanding key water treatment terms and definitions can help in selecting complementary technologies.

Granular activated carbon is made from raw organic materials such as coconut shells or coal that are high in carbon. Heat, in the absence of oxygen, is used to activate the carbon and create millions of microscopic pores in the granules, which is why these filters are sometimes referred to as “charcoal” filters.

Applications: Whole House vs. Point-of-Use

This media is widely used in water filtration and home water filtration system applications for homeowners, agricultural properties, and light commercial buildings that want better water quality from well water or city water, whether as a point-of-use unit at a single faucet (for example, an under-sink filter) or as a whole-house system at the main line. The activated carbon removes certain chemicals as water passes through the filter by trapping, or adsorbing, them in the GAC. Point-of-use units are installed just before the faucet, while a whole house or house water filtration system is installed at the water source or main line to treat water for sinks, showers, bathing, laundry, appliances, and each tap. In city water applications, standard GAC commonly handles chlorine taste and odor, while chloramine treatment usually calls for catalytic Centaur carbon media; in well water applications, sediment reduction and additional UV treatment may also be needed to address bacteria and provide microbial protection. Backwashing filters automatically clean the media bed, and backwashing systems self-clean on a schedule. By contrast, GreensandPlus water filtration systems require regular regeneration with potassium permanganate to maintain performance.

Installation and Sizing Considerations

It is very important that the water be tested, that the type, concentration, and—when iron may be present—the form of contaminants be identified, that dissolved inorganic contaminants may require treatment beyond GAC, and that average water use be known in order to determine the correct size and components of the system. Proper sizing is critical for filtration efficiency, water pressure, system performance, overall water quality, and protection for plumbing and appliances. Where iron is present, system design should also account for oxidation and, if a water softener is installed downstream, avoid exposing raw water to air beforehand. In some cases, a dedicated Birm iron and manganese filtration system may be appropriate. Iron concentrations above 0.3 mg/L can cause orange or rust staining on sinks, laundry, and fixtures, even when the issue is mainly aesthetic in drinking water. Elevated manganese in drinking water can also create water quality concerns and, at higher levels, potential neurological health effects. For more complex groundwater issues, media such as Katalox Light filtration systems for iron, manganese and hydrogen sulfide or oxygen chamber AIO systems for iron and sulfur removal may be considered alongside GAC. This guide explains how GAC systems work, what components and benefits to look for, how features such as the Clack 990 In and Out Valve Head fit into system design, and what to consider for sizing, contaminant levels, integration with other treatment equipment, and maintenance before choosing a house water filter system.

Maintenance and Media Replacement

Maintaining treatment systems is necessary for long-term performance. Eventually, the ability of the GAC to bind and remove chemicals is used up and the GAC needs to be changed. Media replacement should be based on use and water quality. Typical lifespan and maintenance intervals include:

• Granular activated carbon filters: approximately 100,000 gallons or 6–12 months

• Whole-house carbon systems: up to 1,000,000 gallons or around 10 years, depending on service conditions

Higher contaminant or metal levels typically require more frequent maintenance, and acidic well water may also call for pH neutralizers and acid neutralizing filters in addition to GAC.

Pairing with Other Treatment Systems

GAC is often paired with other treated water systems, such as reverse osmosis or UV, as part of a broader treatment solution for healthier water and wider coverage; selecting appropriate water filtration media for clean, fresh water can further tailor performance to specific contaminants, and removing chlorine ahead of RO can also help protect membrane life, and added disinfection may still be appropriate where microbial risks are a concern. Cleaner water also benefits household uses for pets and can help protect a water heater from sediment or related water quality issues.