Activated Carbon Filters

Activated carbon works by adsorption: chlorine, odour and taste compounds attach to the enormous internal surface area of the carbon rather than being strained out. It is the stage that makes water pleasant to drink, and on any system with a reverse osmosis membrane it is also the stage that protects that membrane from chlorine.

Coconut shell or coal based?

Coconut-shell carbon has a finer pore structure and performs better on chlorine, taste and odour, which is why it is the usual choice on drinking-water lines. Coal-based carbon has a broader pore distribution and holds larger organic molecules better, which suits industrial and process duties. Both are sold here by the litre for loading into vessels.

Contact time decides performance

Carbon needs time in contact with the water to adsorb. A vessel sized for a lower flow than it actually sees will pass chlorine through no matter how good the carbon is. This is why a carbon stage is sized on peak flow, and why a cartridge that is too small for a building inlet is a false economy.

Knowing when it is spent

Carbon gives no visible warning — it stops adsorbing long before it looks used, and there is no pressure drop to notice. That is why carbon is replaced on time rather than on symptoms, typically every six months on cartridges and on a longer schedule for media beds that are backwashed.

Carbon media and cartridges are consumables and are outside warranty cover; the vessels and valves around them carry a 2-year warranty.