CFS CTO Carbon Block Water Filters for C1-20, 155597-43, 20 x 2.5, 4 Pack

• SOLID CARBON BLOCK, NOT LOOSE GRANULES - The carbon is pressed into a block, so water is pushed through the media rather than channeling around it as it can in a granular cartridge. That contact is what reduces the chlorine taste and odor that make water unpleasant to drink and cook with, and the block also captures sediment down to 5 micron on the way through.
• FOUR CARTRIDGES PER PACK - At a change every three to six months, four cartridges cover a year and a half to two years. Buying the interval at once costs less per cartridge than replacing one at a time, and it means the spare is on the shelf before the chlorine taste comes back.
• FITS ANY STANDARD 20 BY 2.5 INCH HOUSING - Direct replacement for C1-20, EP-20, HX-CB-25-2010, SP-P5-20, NCP-20, F3WCB32, RIF-10 and 155597-43. If the cartridge you are pulling out measures 20 by 2.5 in, this fits your whole house system. Compatible replacement made by CFS, not an original manufacturer part, and part numbers are used for reference only.
• CHECK THE LENGTH, NOT JUST THE DIAMETER - This is the 20 in slim line cartridge, twice the length of the common 10 in and the same 2.5 in diameter. It is not the 4.5 in big blue size. Measure the one you are pulling out; the two lengths look alike on a photo and will not seat in each other's housings.
• CARBON EXHAUSTS, IT DOES NOT CLOG - A sediment cartridge tells you it is finished by dropping your water pressure. Carbon does not; it simply stops reducing taste and odor while flow stays the same. Change on a schedule rather than waiting for a sign, about every three to six months depending on your water.

CFS carbon block water filter cartridges in the 20 by 2.5 in slim line size, 5 micron, four per pack. The carbon is pressed into a solid block rather than packed in as loose granules, and the difference matters more than it sounds. Water pushed through a granular bed finds the path of least resistance and channels around most of the carbon; a block leaves it nowhere to go, so every drop gets the contact time the media was designed for. That contact is what reduces the chlorine taste and odor that make water unpleasant to drink and cook with, and the block structure also captures sediment down to 5 micron on the way through. The 20 in length is what makes this a whole house cartridge rather than a point of use one. There is twice the carbon of the common 10 in cartridge at the same diameter, so it treats more water before the media is spent and it holds flow better on a house-wide line. Four cartridges covers a year and a half to two years at a change every three to six months. Check the length before ordering, because this is where most wrong orders happen. This is the 20 by 2.5 in slim line size, not the 4.5 in big blue, and not the 10 in. Measure the cartridge you are pulling out rather than going by the model name on your housing. It is a direct replacement for C1-20, EP-20, HX-CB-25-2010, SP-P5-20, NCP-20, F3WCB32, RIF-10 and 155597-43, and it fits any standard 20 by 2.5 in whole house filtration system whether or not your model is named here. Carbon behaves differently from sediment media at the end of its life. A sediment cartridge tells you it is finished by dropping your water pressure; carbon gives no such warning and simply stops reducing taste and odor while the flow stays the same. Change on a schedule rather than waiting for a sign, about every three to six months on typical municipal water and sooner on a heavily chlorinated supply. This is a compatible replacement made by CFS, not an original manufacturer part, and part numbers are used for reference only.