2.5" x 14" Freshwater Reverse Osmosis Membrane

RO water starting to taste flat or salty? TDS meter creeping up? Production down even with fresh pre-filters? Those are the signs of a tired membrane element, the one part of a reverse osmosis system that actually separates dissolved salts and minerals from your water.

The Crystal Quest 2.5" x 14" Freshwater Reverse Osmosis Membrane (CQE-RC-04111, the 2514 element size) is the replacement element listed for the 300 GPD Crystal Quest Whole House Reverse Osmosis System and the 200 GPD Low-Flow Reverse Osmosis System. Because 2514 is a standard element size, it also fits other RO systems built for 2.5 x 14 inch membranes. It is a thin-film composite (TFC) element for municipal and well water that has been pre-filtered and dechlorinated.

At a glance

• The exact element for your system: one per 300 GPD Whole House RO and one per 200 GPD Low-Flow RO
• Rejection with its test conditions: 99% nominal salt rejection (96% minimum) at 550 ppm feed, 150 psi, 77°F (25°C) and 15% recovery
• Freshwater class: for tap and well water under 2,000 ppm TDS
• Long service life: plan on 2 to 3 years; actual life depends on feed water quality, system configuration and usage

What you are looking at

A spiral-wound cylinder. Leaves of TFC membrane are wound around a perforated center tube, with a mesh feed spacer between them to hold a flow channel open. Purified water (permeate) spirals inward and exits through the center tube; everything held back leaves the far end as concentrate. A brine seal on one end seals the element to the housing wall so all feed water passes through it, not around it. It ships in preservative solution with protectors on each end of the permeate tube. The 14" length fits only housings built for it; it is not interchangeable with 2.5" x 21" or 2.5" x 40" elements.

How a reverse osmosis membrane works

Pressure reverses osmosis

Water naturally moves across a semipermeable membrane toward the saltier side. An RO system pushes harder than that osmotic pull, forcing water molecules through the membrane while dissolved ions stay behind. Crystal Quest rates its whole house RO elements at 150 psi operating pressure.

Cross-flow keeps it clean

An RO element does not store what it removes. Feed water sweeps across the membrane and the concentrate carries rejected minerals to drain, which is why one element can run for years. It is also why every Crystal Quest RO system sends about 1 gallon to drain for every 1 to 3 gallons of purified water, depending on your water and settings.

Reading the numbers

Rejection is feed TDS minus product TDS, divided by feed TDS. Element ratings use a single element at 15% recovery so elements compare on equal terms. Colder or higher-TDS water lowers production, and RO water reads 1 to 2 pH points below the feed, because dissolved carbon dioxide passes while buffering minerals do not.

What it reduces

Primary target: total dissolved solids, the sodium, chloride, sulfate, calcium and magnesium ions behind salty or mineral taste and spotting. Crystal Quest whole house RO systems are rated for 96% minimum and 98.5% nominal salt rejection.

Also held back: particles that reach the membrane, including microplastics, are far larger than anything it lets through. The pre-filters take most of them first.

Not designed to handle: free chlorine, which attacks the TFC layer (0.1 ppm maximum); sediment, which belongs to the pre-filters; and iron or manganese above 0.05 ppm or hardness above your system's limit, which foul and scale the surface. Pre-treat these first, or ask us about a Whole House Reverse Osmosis System sized from your water test.

Why Crystal Quest

• Matched to our own systems, straight from our replacement tables, with no cross-reference guessing.
• Numbers you can check: rejection with its test conditions, and full operating limits 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

• 300 GPD Whole House Reverse Osmosis System: one element.
• 200 GPD Low-Flow Reverse Osmosis System: one element.
• Not this element: the 400 GPD Whole House RO uses the 2.5" x 21" Freshwater Reverse Osmosis Membrane.

Check the part number on your current element first. RO membranes and filter cartridges are not returnable under our refund policy, so call us if you are unsure and we will confirm the part.

Standard 2514 format

This is a low-energy freshwater element in the standard 2514 (2.5" x 14") format used in 2.5" membrane housings built for 14" elements, including Crystal Quest systems. Crystal Quest rates its whole house RO elements at 150 psi operating pressure, well below what brackish water and seawater elements are built for, so the pump does less work on tap and well water. A shared format name is a good start, not a guarantee: if your system is not a Crystal Quest model, compare the brine seal position, permeate tube ends and flow direction with your current element, or contact us before ordering.

Storage and handling

Each element ships sealed in its bag in a preservative solution. Keep it sealed until you are ready to install it, store it indoors out of direct sunlight, and never let it freeze. Once an element has been installed and wetted, do not let it dry out. If your system will sit idle for a season, Membrane Preservative is used to protect the elements against damage from bacterial growth.

Common questions

Element specifications

Element performance

Feed water limits for the system

*Service life is an estimate. Actual life depends on feed water quality, system configuration and usage. Performance figures are from the Crystal Quest whole house RO manuals; production falls with colder or higher-TDS water. Element ratings are from the element data sheet. The 600 psi rating is the element's structural limit. Low energy elements are designed to make their rated flow at about 150 psi.