Natural (Alkalinize) Ionizer, Mineralizer and Oxidation Inline Cartridge

Reverse osmosis makes water remarkably clean, and also remarkably bare. The membrane strips out calcium, magnesium and the other minerals that give water its body, so RO water can taste flat and run slightly acidic. This inline cartridge puts minerals back.

The Natural (Alkalinize) Ionizer, Mineralizer and Oxidation Inline Cartridge, part CQE-RC-04054, is filled with a blend of calcite and magnesium oxide. As water flows through, the blend slowly dissolves, adding calcium and magnesium, raising the pH and making the water less corrosive. Its label says it plainly: adds minerals and enhances alkalinity.

At a glance

• Adds calcium and magnesium back to purified water from a natural carbonate mineral blend
• Raises pH and alkalinity, so water is less acidic and less corrosive
• Better-tasting RO water: restores the mineral body that purified water lacks
• Inline and sealed: plumbed on the water line with threaded connectors, replaced as one piece
• An optional stage listed for Crystal Quest under-sink RO systems, the Countertop RO system and water coolers

What you are looking at

A white, sealed inline cartridge with an elbow connector at each end. The label reads "Crystal Quest Natural (Alkalizer) Ionizer, Mineralizer and Oxidation Inline Cartridge" and shows the flow arrow, part number, operating limits and nine numbered replacement steps. Inside, the media is packed in layers between the inlet and outlet, as the cutaway diagram in the photos shows.

How a carbonate remineralizer works

Why RO water runs acidic

An RO membrane holds back dissolved minerals, but dissolved carbon dioxide passes straight through it. In water, carbon dioxide forms a weak acid, carbonic acid. With the minerals gone, nothing is left to buffer that acid, so purified water usually leaves the membrane slightly acidic and "hungry" for minerals.

The reaction inside the cartridge

Calcite and magnesium oxide react with that carbonic acid. Each reaction uses up acid and releases calcium or magnesium ions plus bicarbonate into the water. Bicarbonate is the main form of alkalinity in drinking water: it is what lets water neutralize acid and hold a steady pH. So one gentle reaction does three jobs at once: adds minerals, consumes acidity and builds buffering capacity.

Self-limiting by nature

Carbonate minerals dissolve fastest when water is most acidic and slow down as the water approaches balance. That is why a natural mineral stage raises pH gradually rather than overshooting, and why the media is used up slowly over time instead of all at once.

What it reduces

Primary targets:

• Low pH and acidity in purified water
• The corrosiveness of acidic water toward metal plumbing and fixtures downstream

Also reduced: the flat taste of purified water. The cartridge does this by adding calcium and magnesium from a natural carbonate mineral blend, plus bicarbonate alkalinity, which gives the water a higher pH, more buffering and a rounder taste.

Not designed to treat: contaminants. Chlorine, chemicals, metals, fluoride and dissolved solids are handled by the other stages in your system, such as the RO membrane, carbon and SMART cartridges. It is also not an electric water ionizer: there are no electrodes and no power, only natural minerals dissolving into the water. Use it only on water that is microbiologically safe.

Why Crystal Quest

• Natural minerals, nothing added by machine. The pH rise comes from calcite and magnesium oxide dissolving, the same chemistry that gives spring water its minerals.
• Made for our systems. Crystal Quest lists this cartridge as the optional mineralizing stage for its under-sink RO, countertop RO and water cooler systems.
• Printed guidance on every cartridge. Flow direction, operating limits and replacement steps are on the label.
• 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

• Thunder under-sink RO systems: listed as the optional remineralizer, part CQE-RC-04054, in the Thunder manual and on Thunder system pages such as the Thunder 1000C.
• The Countertop Reverse Osmosis System: listed as its optional remineralizer.
• Bottleless water coolers: listed as an optional cartridge in the water cooler manual.

Placement: we recommend installing it after the RO membrane, where the water has been stripped of minerals, so it remineralizes purified water and adds no load to the membrane. Follow your system's manual for the exact position.

Need the same mineral treatment in a standard drop-in housing instead of an inline cartridge? See the drop-in Natural (Alkalinize) Ionizer, Mineralizer and Oxidation Cartridges.

Common questions