Nitrate Removal Filter Cartridge

Nitrate has no color, no smell and no taste. You only find it with a water test. Most nitrate in drinking water comes from septic systems, feedlots and farm fertilizer reaching groundwater, so private wells in rural areas are where it usually shows up. In the body, nitrate is converted to nitrite, which is why the drinking water limit is set at 10 mg/L measured as nitrogen (45 mg/L as nitrate).

The Crystal Quest Nitrate Removal Filter Cartridge is a dedicated nitrate stage. It is packed with nitrate-selective anion exchange resin, a resin built to grab nitrate even when the water also carries sulfate, the ion that defeats ordinary resins.

At a glance

• Targets nitrate, the fertilizer, septic and feedlot contaminant of rural wells
• Nitrate-selective resin that keeps working on water with moderate to high sulfate
• Built to avoid nitrate dumping, the sudden release that standard resins can suffer when sulfate pushes nitrate back off
• No electricity or drain line: it works in a standard filter housing
• Four sizes, 0.5 to 6 GPM, for countertop, under-sink and whole house housings

What you are looking at

Inside each cartridge is a bed of small, opaque resin beads held in polyolefin inner and outer wraps and polyethylene netting, closed with polypropylene end caps and sealed with Buna-N gaskets. Every bead is a cross-linked polymer sphere covered in charged exchange sites, and those sites are where the nitrate goes. Each end cap has 1-micron pads behind its openings.

How a nitrate filter cartridge works

Ion exchange: chloride out, nitrate in

Nitrate is a negatively charged ion (an anion), so it cannot be strained out like sediment. The resin is a strong base anion exchanger supplied in the chloride form. As water passes through, nitrate ions attach to the resin's positively charged sites and an equal charge of harmless chloride is released in their place.

Why sulfate matters

Ordinary anion resins prefer sulfate over nitrate. On water that carries both, sulfate steadily takes over the sites. Near the end of the run it can push captured nitrate back into the water, so the treated water briefly carries more nitrate than the water coming in. That is called nitrate dumping, and it is the main risk of using the wrong resin for nitrate.

What makes this resin nitrate-selective

Nitrate-selective resin uses a more open, macroporous bead and specially chosen exchange groups that favor nitrate over sulfate. It keeps its nitrate capacity when sulfate is moderate to high and leaves more of the sulfate in the water. That also keeps chloride from climbing too high, which would make treated water less pleasant to drink and more corrosive.

Why life varies

Every site that takes up nitrate or another anion is used. Higher nitrate, higher sulfate and higher flow use the bed faster. That is why each size has its own flow and why testing, not a calendar, tells you when the cartridge is spent.

What it reduces

Primary target: nitrate. This is the dedicated nitrate cartridge; its resin is chosen for nitrate first.

Not designed to treat: bacteria and viruses, hardness, iron, arsenic, fluoride, or chlorine and chemical tastes. A well with nitrate from a septic system or livestock can also carry bacteria, so test for bacteria as well and use this cartridge only on microbiologically safe water.

Is it right for my water?

Start with a lab test that reports nitrate, sulfate and bacteria. If nitrate is your only concern, this dedicated cartridge gives you the most nitrate resin in the space. If you also want chlorine, chemical and heavy metal reduction from the same stage, the Nitrate Removal + SMART Filter Cartridge combines nitrate-selective resin with coconut shell carbon and redox media. For a whole home, talk to us about a nitrate tank system.

Why Crystal Quest

• The right resin for the job. Nitrate-selective resin, not a general anion resin that can dump nitrate when sulfate is present.
• A complete nitrate lineup: this dedicated cartridge, the SMART combination and whole house nitrate systems.
• Full construction disclosure in the Specifications tab.
• Over 1,000,000 people served since 1994. Crystal Quest builds under ISO 9001 quality management, has made water filtration in the USA for over 30 years and offers lifetime support by phone, email or chat.

Where it fits

• Countertop and under-sink systems that take the 2-7/8" x 9-3/4" size.
• Whole house cartridge systems with slim 20" or Big Blue housings.

Choose the size printed on your current cartridge or in your order history: 2-7/8" x 9-3/4" (CQE-RC-04007), 2-7/8" x 20" (CQE-RC-04020), 4-5/8" x 9-3/4" (CQE-RC-04066) or 4-5/8" x 20" (CQE-RC-04069).

Common questions