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Crystal Quest Water Filters
    • Whole house Filters every tap
    • Water softeners For hard water
    • Whole house RO RO for every tap
    • Under-sink reverse osmosis For drinking water
    • Under sink Fits under the sink
    • Countertop Sits by the faucet
    • Shower and bath For shower and bath
    • Inline On a water line

    Whole house

    • Whole house Water filters
    • Whole house Reverse osmosis
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    • All salt-free conditioners
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    Drinking water

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    Specialty filtration

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    All specialty filters

    More ways to filter

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    ZIP code Hardness on record Four levels Soft to very hard
    • Shower filter replacement cartridge
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    Type the code printed on your cartridge.

    Common part numbers

    • Pitcher
    • CQE-RC-04002 SMART cartridge
    • CQE-RC-04000 Carbon block
  • Commercial and industrial

    Every system built to order

    Quotes on request, from a single inline filter to industrial reverse osmosis.

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    Reverse osmosis

    • Brackish water RO
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    Commercial RO

    Commercial systems

    • SMART systems
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    Industrial

    • Industrial filtration
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    Commercial/industrial specialty systems
    • Acid neutralizing (commercial)
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    • Sulfate removal
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  • Full water tests

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    Need help? Get expert support from water filtration specialists (800) 934-0051 help@crystolquest.shop

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  • Whole house
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Need help?(800) 934-0051

Finding a replacement?

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Try the code printed on your cartridge, a product name, or a problem like hard water. Or let us find it for you. Talk to a specialist

Popular searches

  • Shower filter
  • Whole house filter
  • High flow
  • Reverse osmosis
  • In-line refrigerator filter
  • Water softener

Popular replacements

See all replacements
  • Coconut Based 5-Micron Carbon Block cartridge From $22.95
  • SMART cartridge From $59.00
  • Shower Filter cartridge From $29.50
  • Bath Ball® cartridge From $39.50

Quick links

  • Check your water Hardness by ZIP code
  • Well water filter finder A short quiz that matches a system
  • Water test kits Lab tests for city and well water

Popular guides

  • How Often to Change Your Water Filter 14 min read
  • Whole House Water Filter Maintenance 11 min read
  • Hard Water 101 19 min read
  • How to Test Water Hardness at Home 6 min read

Common part numbers

  • CQE-RC-04000 Coconut Based 5-Micron Carbon Block cartridge
  • CQE-RC-04002 SMART cartridge
  • CQE-RC-04045 Shower Filter cartridge
  • CQE-RC-04052 Bath Ball® cartridge

  1. Home
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Finding a replacement?

Find the system you own, then confirm its replacement. A model or cartridge code helps.

Find replacements for my system Find your model or part number

Need help with your system?

For leaks or a system that is not working, send our team the model and a description of the problem.

Get product support Visit the Help Center

Results for “reverse osmosis”

219 results

All Products Guides Pages

Guides

  • Guide · July 27, 2025

    How to Sanitize a Reverse Osmosis System & Clean the Storage Tank

    Sanitize your RO storage tank the right way. Bleach ratios and step-by-step cleaning for both atmospheric (whole-house) and bladder (under-sink) systems.
  • Guide · July 17, 2026

    How to Size a Commercial Reverse Osmosis System (GPD, Recovery, and Feed Water)

    Turn a vague water need into a real gallons-per-day spec. A manufacturer walks through peak demand, recovery, feed-water derating, and pre-treatment.
  • Guide · July 25, 2025

    How to Replace Reverse Osmosis Pre- and Post-Filters: A Step-by-Step Guide

    Slow flow, funny taste, climbing TDS? Most RO problems trace back to filters that overstayed their welcome. Swap pre- and post-filters in 30 minutes.
  • Guide · July 25, 2025

    How to Clean a Reverse Osmosis Membrane: Maintenance for Long-Term Performance

    Flow dropping, TDS climbing, or taste off? Before you replace your RO membrane, try cleaning it. Here's which cleaner to use and how.
  • Guide · June 16, 2026

    Filtered Water vs Purified Water: What's the Difference?

    Is filtered water the same as purified water? Not exactly. One is a method, the other a standard the water must meet. Here is the difference.
  • Guide · July 25, 2026

    Best Water Filters for Microplastics (2026 Buyer's Guide)

    Microplastics are in your tap water and your bottled water. Compare reverse osmosis, ultrafiltration, carbon, and ceramic filters, with real removal rates, prices, and a guide to picking the right one for...
  • Guide · July 14, 2025

    Nanofiltration for PFAS Removal: How Selective Membrane Technology Works

    Nanofiltration sits between ultrafiltration and reverse osmosis on the membrane spectrum. Here is how it stacks up against RO for PFAS removal and where each technology fits.
  • Guide · August 5, 2025

    What Is Nanofiltration? A Guide to NF Water Filtration

    Nanofiltration (NF) is a membrane process that sits between ultrafiltration and reverse osmosis, reducing hardness, sulfates, and PFAS at lower pressure than RO. Here is how it works, what it removes, and...
  • Guide · June 26, 2026

    Is Softened Water Safe to Drink? Sodium Levels Explained

    Your water softener swaps hard minerals for a little sodium. Here is how much it adds, who should watch it, and how to get low-sodium water at the tap.
  • Guide · July 1, 2026

    Best Under-Sink Water Filter: How to Choose the Right System

    A manufacturer's guide to choosing an under-sink water filter: cartridge vs reverse osmosis, media by function, avoiding proprietary lock-in, and fit.
  • Guide · June 16, 2025

    A Comprehensive Guide to Water Contaminants and Filtration Strategies

    From lead and PFAS to nitrates and chlorine, here is what can end up in your tap water, why each one matters, and the filtration that removes it.
  • Guide · July 29, 2026

    Greenhouse and Hydroponic Water Treatment: Managing TDS, EC, and Chloramine for Healthy Crops

    A commercial grower's guide to greenhouse and hydroponic source water: EC and TDS, alkalinity, chlorine and chloramine, and sizing RO to your operation.
  • Guide · July 11, 2025

    Ion Exchange for PFAS Removal: What It Does & When It Fits

    Ion exchange for PFAS is one of four EPA-approved removal technologies. Here's how anion exchange resin works, where it shines, and how it compares to carbon and reverse osmosis.
  • Guide · July 22, 2026

    Water Treatment for Dialysis: Meeting Hemodialysis Water-Quality Requirements

    Dialysis water must be far purer than water that is safe to drink. Here is the standard that governs it and the treatment train that produces it.
  • Guide · July 26, 2026

    Spot-Free Car Wash Water: How RO and DI Rinse Systems Work

    Those white spots after a rinse are dried minerals. Here is how deionized and RO water make a spot-free rinse, and how to size a system.
  • Guide · September 22, 2026

    What Is Brackish Water? Salinity, Sources and Safety

    Saltier than fresh water, not as salty as the sea. How to tell if your water is brackish, and which filters can and can't take the salt out.
  • Guide · July 16, 2026

    Types of Water Explained: Spring, Artesian, Mineral, Purified, and Distilled

    A plain-language guide to every type of water, sorted by where it comes from and what has been done to it, plus how to choose.
  • Guide · July 6, 2026

    Best Water Filter for Apartments: A Renter's Guide

    No drilling and no landlord conversation required. Here is every water filter that works in a rental, and how to match one to your water and your lease.
  • Guide · June 19, 2026

    10 Benefits of Water Filtration (And How to Choose the Right System)

    Filtration closes the gap your utility leaves behind, cutting contaminants like lead and PFAS that meet legal limits but you would rather not drink.
  • Guide · June 26, 2026

    Chromium-6 in Drinking Water: Health Risks and How to Remove It

    The Erin Brockovich chemical is still in many US water supplies. Here is what hexavalent chromium does to your health and how to filter it out.
  • Guide · July 20, 2026

    What Kind of Water Should You Use in a Humidifier?

    Tap water leaves white dust on your furniture and scale in the tank. Here is which water to use in a humidifier, and how to make your own at home.
  • Guide · August 5, 2025

    How Does Ultrafiltration Work? A Guide to UF Water Filtration

    Ultrafiltration strains out bacteria, cysts, and particles without stripping the minerals your water already has. Here's how UF works and where it fits.
  • Guide · August 4, 2025

    What Is Microfiltration? How It Works and What It Removes

    A clear guide to microfiltration: how the membranes work, what they remove, and where they fit alongside ultrafiltration, nanofiltration, and reverse osmosis.
  • Guide · July 16, 2026

    Can You Drink Deionized Water? Safety, Taste, and Better Options

    Deionized water will not poison you, but it is built for labs, not your glass. Here is what happens when you drink it and the smarter everyday option.
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  • Built in the USA

    Supporting American jobs and contributing to our nation's economic growth.

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