Filtration Technology
The science behind water filtration: membrane technology, ion exchange, activated carbon, DI resin, and specialty media.
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24 articles
Membrane FiltrationSilt Density Index (SDI): Test, Formula and RO Limits
How the silt density index test works, how to calculate SDI from two timed 500 mL samples, and the reading most RO membranes call for.
Membrane FiltrationMembrane Fouling: 4 Types, Warning Signs, Prevention
Scale, particles, organics or biofilm? How each type of membrane fouling shows up in flow, salt passage and pressure drop, and the pretreatment that stops it.
Media & ResinCatalytic Carbon Water Filter: How It Works
Catalytic carbon is the activated carbon built for chloramine and rotten-egg odor. See how it works, how it beats standard carbon, and when you need it.
Media & ResinCoconut-Free Water Filters: Carbon Options
Coconut allergy or preference? Coconut is not a tree nut, but if you want a coconut-free water filter, Crystal Quest can build one.
Media & ResinWhat Is KDF Water Filter Media?
KDF water filter media uses a copper-zinc redox reaction to reduce chlorine and heavy metals, even in hot water. Here is how it works and what it does not.
Media & ResinHow Activated Carbon Water Filters Work
How activated carbon water filters work, what they remove (chlorine, chloramine, VOCs, taste), what they can't, and GAC vs carbon block vs catalytic carbon.
Ion ExchangeWhat Is Cation Exchange Resin? SAC vs WAC, Softening vs DI
Cation exchange resin removes positive ions like calcium and magnesium. Learn how SAC and WAC resins work, regeneration, and where they are used.
Media & ResinAnion vs Cation Exchange: What's the Difference?
Anion vs cation exchange explained simply: anion resin removes negative ions like nitrate and PFAS, cation resin removes positive ions like calcium.
Ion ExchangeAnion Exchange Resin: Types, Uses, and How It Works
Anion exchange resin removes nitrate, sulfate, tannins, and arsenate. Learn the two regeneration cycles (salt brine vs caustic) and how to pick the right grade.
Ion ExchangeHow Deionization (DI) Works: The Ion Exchange Process
See how deionization (DI) works: cation and anion resin swap ions to make ultra-pure water. Covers RO to DI, mixed-bed polishing, and measuring purity.
Media & ResinWhat Is DI Resin? A Buyer's Guide to Deionizing Resin
Discover how DI resin works, what it removes, and why it’s essential for pure water in labs, aquariums, car washes, and industrial systems.
Membrane FiltrationHow Does Ultrafiltration Work?
Ultrafiltration uses a fine membrane to remove bacteria, cysts, and particles from water while preserving minerals. Here's how UF water filtration works.
Membrane FiltrationWhat Is Nanofiltration? Guide to NF Water Treatment
Nanofiltration sits between ultrafiltration and reverse osmosis, cutting hardness and PFAS at lower pressure than RO. See what it removes and where it fits.
Membrane FiltrationHow Does Reverse Osmosis Work? Membrane Technology Explained (2026)
How does reverse osmosis work? Learn the membrane science, pore sizes, pressure requirements, multi-stage process, and how RO compares to UF, NF, and MF filtration.
Membrane FiltrationWhat Is Microfiltration? How It Works
Microfiltration removes sediment, bacteria, and suspended solids through 0.1 to 10 micron membranes. Learn how it works and how it compares to UF, NF, and RO.
Membrane FiltrationNanofiltration vs Reverse Osmosis for PFAS Removal
Compare nanofiltration and reverse osmosis for PFAS removal. See how pore size, energy use, recovery rates, and contaminant coverage differ.
Ion ExchangeIon Exchange for PFAS Removal: What It Does & When It Fits
Ion exchange for PFAS is one of four EPA-approved PFAS removal technologies. See how anion resins work, when it fits, and how it compares to RO and carbon.
Media & ResinActivated Carbon for PFAS Removal: Types and How It Works
Activated carbon captures up to 90% of longer-chain PFAS. Learn how the media traps PFAS, which carbon type performs best, and how to pick a system.
Membrane FiltrationDoes Reverse Osmosis Remove PFAS?
Learn how reverse osmosis physically blocks up to 99% of PFAS from drinking water. Compare under-sink, countertop, and whole house RO systems.
Media & ResinNAC vs TAC: Salt-Free Water Conditioning Media Compared
NAC and TAC are two names for the same salt-free scale prevention approach. See what independent testing shows and how to pick the right system for your water.
Ion ExchangeWhat Is Ion Exchange? How It Works & When to Use It
How ion exchange works, what it removes, and when it fits your water. From softeners to PFAS, explained by Crystal Quest engineers.
Media & ResinWhat Is NAC Media? Salt-Free Water Conditioning Explained
NAC (Nucleation Assisted Crystallization) prevents hard water scale without salt. Learn how it works, how it compares to softeners, and if it's right for your water.
Media & ResinNAC Media Technical Guide: Chemistry & Specifications
How NAC media prevents scale at the molecular level. Chemistry, operating parameters, NAC vs TAC, feed water requirements, and Eaglesorb ES3 specifications.
Membrane FiltrationMembrane Technology in Multistage Filter Systems
Compare ultrafiltration, nanofiltration, and reverse osmosis in multistage water filter systems. Find which membrane type fits your water quality goals.