Activated carbon block vs. granular activated carbon filter

How do you differentiate between an Activated Carbon Block and a Granular Activated Carbon filter?

Activated carbon block vs. granular activated carbon filter

Activated carbon block vs. granular activated carbon filter

Granular activated carbonCarbon block filter
Loose granules of carbon/ grounded carboncompressed block of carbon
higher flow rate lower flow rate
Post and pre-filterPrefilter
Improve taste and odor by removing chlorineFilter sediment, chlorine, pesticides, heavy metals and more
adsorbAdsord and filter

Both activated carbon block and granular activated carbon filters (GAC) are types of carbon filters made of grounded carbon. They are also designed to filter chlorine odor and taste, pesticides, herbicides, and cleaning detergents.

An activated carbon block is made of a compressed block of ground carbon, and GAC is made of loose granules of carbon or grounded carbon.

An activated carbon block is ground finely, heated up, and compressed into a solid block. Granular activated carbon filter (GAC) is not finely grounded and compressed, it is just in powder or granules.

The carbon block is fine and tightly compressed water takes a long time to flow through the filter, meaning more contaminants are removed. Granular activated carbon is made up of loose granules, so contaminants can easily escape. This also explains why carbon block has high adsorption compared to GAC.

Carbon block water takes a long time to go through the filter, leading to a lower flow rate. Water flows with resistance because it is in the form of a block. GAC has a higher flow rate (water flows freely without resistance).

The loose nature of GAC and the high flow rate mean the media can filter more water while carbon block can purify less water.

Remember, even if GAC produces more water, it is not effective compared to carbon block.

Granular activated carbon doesn’t have good contact time with water, so it has a chance of lasting longer. The carbon block has a long time of contact with water, and more contaminants will be adsorbed, making it not last longer.

The capacity of a carbon block filter is higher than granular activated.

Granular water flows from the bottom through the media and gets out from the top, while Activated Carbon Block water flows through the media called radial flow.

GAC is used as a post filter. It provides final polishing before the filtered water is delivered to the faucet. Under-sink reverse osmosis is the last filter after the storage tank that helps remove any tastes or odors the water may have picked up while sitting in the storage tank. In some systems, it is used as a pre-filter but comes before activated carbon since it cannot provide better purification.

The GAC filter has granular or powdered carbon inside, while the carbon block comes in the form of a block.

An activated carbon filter is used as a post-filter that can adsorb and filter. What do I mean by filtering? Carbon block can be used to filter sediment but requires a specially added layer or blended material.


The carbon block has a low flow rate and better purification, while granular activated carbon has a high flow rate but less purification.

Each filter has its use and is used in different stages of water purification. A carbon block is used as a pre-filter and granular activated carbon is used as a post-filter or polishing filter.

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