| Item | Detail |
|---|---|
| Activated carbon fibre | 99.5% free-chlorine removal at start of flow in SGS testing; 90.6% after 5 tons in separate tests |
| Calcium sulfite | Ceramic balls that react with free chlorine and keep working in hot water |
| Vitamin C | A gel or media that dissolves into the water; a conditioning consumable, not a filter |
| PP cotton | The pre-stage that traps rust, sand and scale particles; discolours visibly as it loads |
| Mineral and metasilicate beads | Water conditioners, not chlorine filters |
| Common stack | PP cotton first, then a chlorine medium, then optional conditioning beads |
The Comparison at a Glance
All three media sit in a replaceable cartridge inside the handle or head, and the water passes through them on the way to the nozzles. They are not equivalents. Two of them act on free chlorine by different chemistry, and the third works by adding something to the water rather than taking something out.
| Aspect | Activated carbon fibre | Calcium sulfite | Vitamin C |
|---|---|---|---|
| What it targets | Free chlorine, odour, taste | Free chlorine | Nothing is removed; it dissolves in |
| How it works | Adsorption onto a large fibre surface area | Chemical reaction with free chlorine | Gel or media dissolves slowly into the flow |
| Hot water | Effectiveness varies with temperature | Keeps working in hot water | Dissolves faster in hot water |
| Tested figures | 99.5% at start of flow, SGS; 90.6% after 5 tons in separate tests | Media passed a 16-item hygiene test and RoHS screening | No chlorine test figure is claimed |
| Visible indicator | Little to see | Little to see | Visibly shrinks as it dissolves |
| Service life driver | Water volume through the cartridge | Water volume through the cartridge | Dissolution rate, so it goes faster in hot showers |
| Best role | The main chlorine stage | The main chlorine stage where showers run hot | An added conditioning element, usually alongside others |
What Each One Is Actually Doing
Activated carbon fibre works by adsorption: chlorine attaches to an enormous internal surface area as water passes. That gives strong performance at the start and a decline as capacity fills, which is exactly what the test data shows. SGS testing to GB/T 5750.11-2023 on the ACF ZHONGHE uses measured 99.5% free-chlorine removal at the start of flow, and separate third-party testing showed over 96.8% initially and 90.6% after five tons of water. Carbon also addresses odour and taste, which no other media here does.
Calcium sulfite works by chemical reaction rather than adsorption, and its practical advantage is temperature. It continues reacting with free chlorine in hot water, where some media lose effect, and that matters because almost nobody showers cold. The calcium sulfite balls ZHONGHE uses have passed a 16-item drinking-water-grade hygiene test and RoHS screening.
Vitamin C is the odd one out and should be understood as such. Nothing is filtered: a gel or a media blend dissolves slowly into the flow, releasing vitamin C into the water. It is a water-conditioning consumable, and it dissolves faster in a hot shower, which shortens its life. Cosmetic and health claims are frequently attached to it in retail listings and are not supported by anything a factory water test can show, so treat the honest description as the whole claim.
Which to Choose
Start with PP cotton regardless. If your supply carries any rust, sand, or loose scale, a white polypropylene pre-stage is the highest-value part of the whole cartridge, because it protects the nozzles and it tells you when to change by discolouring. Many stacks put it first for exactly that reason.
For free chlorine, choose activated carbon fibre if you want the strongest tested reduction and also want odour and taste addressed. Choose calcium sulfite, or a stack containing it, if the priority is consistent performance in hot water. A combined stack gives you both, and combined cartridges are common precisely because the two media complement each other. Mineral and metasilicate beads are pleasant additions but are conditioners, so do not rely on a bead-only cartridge for a chlorine claim.
Add vitamin C if you like the idea of it, understanding that it is a conditioner rather than a filter and that it will not be doing chlorine work. Whatever you choose, buy by the model code so the cartridge fits the chamber, keep a spare, and remember all of these are consumables whose performance declines with throughput. ZHONGHE catalogues activated carbon, PP cotton, mineral bead, and magnet cartridges as their own refill items alongside the heads.