Follow a Consistent Water Filter Replacement Schedule
Most water filters come with a water filter replacement schedule recommended by the manufacturers. For example, for the Hexagon 8-Stage Pi-water Purifier replacement cartridge, the manufacturer recommends that owners replace it after reaching 10,000 liters or 12 months, whichever is earlier.
However, many water filter owners neglect to follow a consistent replacement schedule. Sometimes, they simply forgot. In other cases, it is due to not fully understanding how their water filter system works.
How Water Filters Work
There are four main types of filtration and they employ a mixture of physical and chemical techniques. Here, we will just look at activated carbon filtration and ion resin filtration.
Activated Carbon
Most common household water filters use activated carbon granules based on charcoal. Charcoal is like a cross between the graphite “lead” in a pencil and a sponge. It has a huge internal surface area, packed with nooks and crannies, that absorbs and traps chemical impurities.
But while charcoal is great for removing many common impurities (including chlorine-based chemicals introduced during waste-water purification, some pesticides, and industrial solvents), it can’t cope with “hardness” (limescale), heavy metals (unless a special type of activated carbon filter is used), sodium, nitrates, fluorine, or microbes.
The main disadvantage of activated carbon is that the filter eventually clog up with impurities and have to be replaced.
Ion Resin
Ion exchange filters are particularly good at “softening” water (removing limescale). They split apart atoms of a contaminating substance to make ions. Then they trap those ions and release, instead, some different, less troublesome ions of their own—in other words, they exchange “bad” ions for “good” ones.
How do they work? Ion exchange filters are made from lots of zeolite beads containing sodium ions. Hard water contains magnesium and calcium compounds and, when you pour it into an ion-exchange filter, these compounds split apart to form magnesium and calcium ions. The filter beads find magnesium and calcium ions more attractive than sodium, so they trap the incoming magnesium and calcium ions and release their own sodium ions to replace them. Without the magnesium and calcium ions, the water tastes softer and (to many people) more pleasant. This soft water is valued by coffee enthusiasts who believe the lack of minerals can prevent limescale build-up from clogging up coffee machines.
Ion exchange filtration requires you to recharge the filter periodically with more sodium ions, typically by adding a special kind of salt. A more practical solution is to replace the ion-exchange filter on a regular basis.
Hexagon 8-stage Pi-water Replacement cartridge
The Hexagon 8-stage Pi-water replacement cartridge has 8 filtration layers (video explanation here), namely:
- 1st Layer: Ceramic Filter filters out bacteria, micro-particulate contaminants, sludge and rust.
- 2nd Layer: Ion Exchange Resin adjusts the Calcium and Magnesium content to soften water for better taste.
- 3rd Layer: Activated Granular Carbon absorbs chlorine, odours and colours.
- 4th Layer: Mineral Element infuses water with ionic minerals and trace elements to mineralised the water.
- 5th and 6th Layers: KDF + Anion Minerals + EC3000 FIR Energy Bead neutralise organic and inorganic chemicals, heavy metals and free radical damage. Energises water to break it into smaller molecular clusters.
- 7th Layer: Activated Granular Carbon performs secondary adsorption of chlorine, unpleasant odours and colours.
- 8th Layer: Magnetic Stone creates magnetic field to further break down water molecular clusters.
As we had learned earlier, when it comes to activated carbon filtration and ion-exchange filtration, it is important to replace the filter cartridge on a consistent basis due to:
- The ceramic layer, as the first layer, filters out most of the bacteria and micro-particulate contaminants. However, this layer gets worn down after repeated rounds of cleaning and brushing.
- The carbon filter layer clogs up eventually with impurities, and also traps bacteria over time (despite most bacteria having been filtered out by the first layer – ceramic filter).
- The ion exchange filter layer requires “re-salting” and re-charging with more sodium ions (adding a special kind of salt).
The manufacturer’s recommended replacement schedule for the Hexagon 8-stage Pi-water replacement cartridge is every 10,000 liters or 12 months, whichever is earlier
CNA News Article – Why Filtered Water May Not Be As Clean As You Think
On 28 May 2021, Singapore’s CNA (Channel News Asia) ran a news article on Why Filtered Water May Not Be as Clean or Beneficial as You Think.
In a test on filtered water from five households (whose filters include activated carbon), the article reported that three households had a bacterial count ranging from 9,000 to 25,400.
Guillaume Drillet from SGS Testing and Control Services, who led the tests, noted that the household with the highest bacteria count had used a filter that was a month overdue for a change. He hence highlighted the importance of following the manufacturers’ proposed replacement schedule.
“The longer you keep your filter running, the higher probability that you’ll have a regrowth of bacteria,” he said. “So it’s very important to follow the schedule proposed by manufacturers.”
Guillaume Drillet, SGS Testing and Control Services