Purikor 6-Stage Reverse Osmosis + UV System

Purikor 6-Stage RO + UV at a glance

It's tempting to assume the UV lamp's job is catching viruses the reverse osmosis membrane might miss — but that's not actually the story here. The 5-Stage's own RO membrane already handles bacteria, protozoa, and cysts at over 99% and excludes viruses effectively on its own; viruses aren't the difference between our two RO systems. The real difference is where the UV lamp sits: after the storage tank and the post-filter carbon, not before them. Everything upstream — the membrane itself — is identical on both systems. What the 6-Stage adds is coverage of the stretch downstream of it.

That stretch is worth taking seriously for two reasons. First, the water reaching the tank has already been de-chlorinated by the membrane, so nothing is suppressing regrowth anymore. Second, it then sits in a 12-litre tank for hours before it's used — and storage time is exactly the variable a classic study in the Journal of the American Water Works Association found drives bacterial regrowth, with counts in household storage tanks climbing by several orders of magnitude over just four to seven days of stagnation, regardless of tank material. On the 5-Stage, the post-filter carbon is the last thing the water touches before your faucet, with nothing downstream of it. On the 6-Stage, the UV lamp is.

UV disinfection itself is well studied and, done properly, highly effective — a point-of-use treatment study found comparable systems inactivating over 99.9999% of bacterial pathogens and over 99.99% of viral pathogens passing through. We won't quote a specific log-reduction figure for our own lamp, though, because Purikor doesn't publish a dose rating (mJ/cm²) for the R-PK-UV-6W — so we're telling you what it does and where it sits, not a number we can't verify for this exact part.

One thing worth understanding about UV maintenance specifically: a failing lamp doesn't necessarily go dark. Research on germicidal UV-C output degradation has found it fades gradually as the internal mercury vapor and electrodes age — a lamp can keep producing visible light well after its germicidal output has dropped below an effective dose. That's exactly why this lamp is replaced on a 12-month schedule rather than when it visibly fails: “it's still lit” isn't evidence it's still working, in a way that's truer of this stage than anything else in the system.

See the full comparison across all four systems for what “partial” and “final-stage UV” mean in practice.

Also in Drinking Water Systems