Double Cartridge Undersink Filter

Double Cartridge Undersink Filter
Item Code: US-0030-678

Compare At: $179.00
Your Price: $109.95

Model / Capacity / Life
US-306 Plus / 10K gal / 1-3 Years
US-307 Ultra / 20K gal / 2-4 Years (+$20)
US-308 Ultimate / 30K gal / 3-5 Years (+$40)

Product Description

CRYSTAL QUEST® Double Replaceable Cartridge Undersink Water Filter system eliminates the impurities of tap water to offer great taste and pureness. The perfect solution for any household, it is quick and easy to install and use, attractive, convenient, and effectively removes hundreds of contaminants from water. This solid state water filter uses the latest technologies that blend the adsorption capabilities of coconut shell activated carbon with REDOX and more.


  • 7 Stages of filtration. First, through a a solid carbon cartridge for removing volatile organic carbon compounds (VOC's, insecticides, pesticides and industrial solvents). Then, through a 6-stage cartridge, removes hundreds of contaminants from water.

  • A diverter valve near the aerator switches between filtered and unfiltered water.

  • Comes in models that conveniently filter 10,000, 20,000 or 30,000 gallons. When the replaceable filter cartridge is used up, the flow of water will automatically either stop or slow down greatly. Great for homes, apartments or office use.


  • Dimensions: 10"L x 14"H(10"+ 4" to change cartridge) x 5"W
  • Weight: 9 lbs
  • Flow rate: 0.75 to 1 gallon per minute

Seven-Stage Water Filtration Process

Double Cartridge Undersink Filter
In stage 1, water travel through a solid carbon cartridge for removing volatile organic carbon compounds (VOC's), insecticides, pesticides and industrial solvents.

In stage 2, water flows through pre and post one - micron filter pads (1 micron equals 1/25,000th of an inch), which removes suspended particles such as silt, sediment, cyst (Giardia, Cryptosporidium), sand, rust, dirt, and other un-dissolved matter.

In stages 3 and 4, water flows through a bed of media made of a special high-purity alloy blend of two dissimilar metals - copper and zinc (KDF-55D ®, and KDF-85D ®.) KDF is a major advancement in water treatment technology that works on the electro-chemical and spontaneous-oxidation-reduction (REDOX) principles. Chlorine is instantaneously and almost inexhaustibly oxidized.

Tests on KDF/GAC cartridge have shown 99+% chlorine removal past 20,000 gallons of water. In comparison, carbon cartridges of comparable volumes drop below 90% effectiveness after only 4,000 gallons. Click here for test data on the GAC/KDF cartridge.

Iron and hydrogen sulfide are oxidized into insoluble matter and attach to the surface of the media. Heavy metals such as lead, mercury, copper, nickel, chromium, cadmium, aluminum, and other dissolved metals are removed from the water by the electrochemical process. They are attracted to the surface of the media, much like a magnet. The media inhibits bacterial growth throughout the entire unit. In fact, it has been shown to be reduced up to 90%, eliminating the need for silver, which is commonly used in carbon-only filters (silver is considered a pesticide by the EPA and, as such, must be registered with them).

Is copper or zinc added to the water in any significant amount? No! On 2.3 ppm chlorinated water, <0.05 mg/l copper and only 0.46 mg/l zinc were measured. The EPA aesthetic levels are 1.0 mg/l for copper and 5.0 mg/l for zinc. Both zinc and copper are essential minerals for good health - the FDA recommends a daily intake of 15 mg of zinc and 2 mg of copper. Click here for more information on KDF filtration.

In stage 5, water flows through ion exchange resins, reducing heavy metals such as lead, copper, aluminum, and water hardness.

In stage 6, water flows through granulated activated carbon (GAC). GAC is universally recognized and widely used as an effective adsorbent for a wide variety of organic contaminants, such as chlorine (99.9%), chemicals linked to cancer (THM's, benzine) pesticides, herbicides, insecticides, volatile organic compounds (VOC's), PCB's, MTBE's and hundreds of other chemical contaminants that may be present in water causing bad taste and odors in your drinking water.

Carbon is extremely porous and provides a large surface area for contaminants to collect. Carbon-only filters must also use their capacity for chlorine removal, resulting in a shortened life. They also may use a bituminous coal carbon, which is good at removing chlorine, but not as effective at removing chemicals. We use a high-grade coconut shell carbon that is most effective at removing chemicals. Coconut shell carbon provides a significantly higher volume of micro-pores than either coal, wood or lignite based carbon. As a result, it is more effective than other carbon types in removing trihalomethanes (THM's) and other chemicals from municipally supplied water. Since our REDOX media removes the chlorine before it reaches the carbon, the carbon capacity is not wasted on chlorine and is free to concentrate more effectively on organic contaminants. Click here for more information on GAC filtration.

In stage 7, water flows through another one-micron filtration pad for further reduction of undesirable particles. The end result is a great reduction or total elimination of a wide variety of contaminants.

Easy Installation

Double Cartridge Undersink Filter
The CRYSTAL QUEST® undersink water system is very simple to hook up and use. It installs in minutes on all standard faucets.

  • Hooks up to separate chromed long reach faucet
  • Quick connect fittings for easy installation
  • Installs out of sight under the sink
  • Easy installation kit included

  •   Replacement Parts & Accessories

    9 3/4" x 2 7/8" 5-Micron Solid Carbon Block Filter Cartridge
    Compare At: $19.95
    Your Price: $16.00
    9 3/4" x 2 7/8" Multi Stage PLUS Filter Cartridge
    Compare At: $57.00
    Your Price: $50.00
    9 3/4" x 2 7/8" Multi Stage ULTRA Filter Cartridge
    Compare At: $77.00
    Your Price: $71.00
    9 3/4" x 2 7/8" Multi Stage ULTIMATE Filter Cartridge
    Compare At: $97.00
    Your Price: $91.00

    Not All Water Filter Systems Are Created Equal!

    Crystal Quest® water filters remove hundreds of contaminants and LAST A LONG TIME. The unique high capacity and multi-stage design means no more over-priced and less effective water filters with replacement filter cartridges that have to be replaced every 100 to 500 gallons!

    Pure Water Essentials offers Crystal Quest® water filtration products because Crystal Quest utilizes the latest technologies in the water industry coupled with 30 years of manufacturing expertise to provide you with high capacity, the most effective, healthiest and great-tasting water conveniently and at the most affordable price. Crystal Quest products are attractive, easy to install and use.

    Crystal Quest Water Filter Reviews

    The CRYSTAL QUEST® Pitcher Water Filter and Shower Filter were awarded "Best Buys" in the August 2006 issue of Consumers Digest magazine.

    The CRYSTAL QUEST® Pitcher Water Filter, Shower Filters, Faucet Mount Water Filters, Countertop Plus Water Filter, Reverse Osmosis Filters, Refrigerator Filters, and Travel Water Filters have been recommended in "The Drinking Water Book - How to Eliminate Harmful Toxins From Your Water" (second edition 2006) by Colin Ingram, on pages 118, 119, 120, 121, 122, 134 and 160.