If you have looked into shower filters, you have probably seen these three names. Most companies list them without explaining what they do or why they are used together. Here is the plain English version.
Stage 1: KDF-55 Media
KDF-55 (Kinetic Degradation Fluxion, media grade 55) is a high-purity copper-zinc alloy in granular form. When water passes through it, an electrochemical reaction converts free chlorine into chloride, which is harmless at the concentrations found in tap water.
KDF-55 removes up to 98% of free chlorine. This is the primary disinfectant added to Australian water supplies, and the primary chemical responsible for stripping your scalp's natural oils with every shower.
KDF-55 also inhibits the growth of bacteria and algae within the filter itself, which extends the filter's effective life and keeps it clean between replacements.
Stage 2: Calcium Sulphite
Standard carbon filters are good at removing free chlorine, but they struggle with chloramines. Chloramines are compounds formed when chlorine reacts with organic matter in water. Many Australian water utilities use chloramines instead of, or in addition to, free chlorine because they are more stable over long distribution networks.
Calcium sulphite targets chloramines directly. It reacts with monochloramine to produce harmless compounds: calcium sulphate, ammonium chloride, and water. It also addresses trihalomethanes (THMs), byproducts of chlorination that survive most filtration methods.
If KDF-55 is the first line of defence, calcium sulphite is what catches what gets through.
Stage 3: Activated Carbon
Activated carbon works through adsorption. Its surface is covered in microscopic pores that trap contaminant molecules as water passes through. A single gram of activated carbon has a surface area of approximately 500 to 1,500 square metres.
This stage captures heavy metals including lead, mercury, iron, and copper, which can be present in Australian water supplies, particularly in older properties with legacy pipework. It also removes volatile organic compounds and any residual chlorine compounds that passed through the first two stages.
Why all three stages matter
Single-stage filters make a trade-off. They remove some things well and miss others. The three-stage sequence is designed so that each stage addresses the compounds the previous stage does not efficiently target. KDF-55 handles free chlorine. Calcium sulphite handles chloramines and THMs. Activated carbon handles heavy metals and residual organics.
The result is water that has been cleared of the primary chemical stressors on your scalp and hair, without reducing pressure, adding anything to the water, or requiring any tools to set up.