Water Filtration - Facts and Myths
Tube Size
All Fountain Filters filters and purifiers use 1/4" diameter tubing and fittings. This is to slow the rate of flow through the cartridge to optimise contact time with the filtration media for efficient adsorption of chemicals.
At typical public water supply pressures the flow rate from the tap will be 3 to 4 litres a minute. 4 litres a minute is the fastest flow rate for any top quality carbon cartridge to be effective.
We see some vendors boast of using 3/8" tubing or more for faster flow rates but then advise you to turn the incoming supply down to 2 litres/minute for effective adsorption!
Fountain Filters water filters use carbon block technology (see below) and will produce clean filtered water to 4 litres/minute with maximum efficiency.
Activated Carbon
Basically, this is charcoal. The most used form in the UK is Bituminous (coal) Granular Activated Carbon or GAC.
Activated carbon is made by grinding bituminous coal, peat, or peanut or coconut shells and baking in controlled conditions to 540C in the absence of oxygen which bakes off the impurities.Then superheated steam at 870C activates the carbon and creates a massive network of pores that greatly increases the surface area of the carbon. This surface area is why carbon can absorb such large quantities of various compounds.
Coconut shell carbon is, by far, the superior carbon and adsorbs the widest spectrum of chemicals the most efficiently.
The newest and best activated carbon technology is Coconut Shell Activated Carbon Block. This is coconut shell GAC which has been further pulverised into smaller particles, then fused and then extruded. The result is all the top chemical adsorption qualities of coconut shell activated carbon but with finer particles giving a much larger surface area and much more activated carbon in the same volume as GAC; and with smaller micron ratings and a longer service life.
An additional benefit of carbon block is that the water is distributed evenly through out the media without 'Water Channeling'.
GAC is a loose media (like sand) and can suffer from 'Water Channeling" where the water keeps to the same waterways through the media. This results in some of the media not being used and leads to early depletion.
At Fountain Filters we use 10 micron coconut shell activated carbon block cartidges or better in all the filter systems except Pearl-M Heavy Metals filter which uses a special mixed media GAC/Phosphate cartridge.
Reverse Osmosis Purifiers which do not need carbon block as the membrane does the work.
GAC is very effective for:
Volatile Organic Chemicals - pesticides, ie herbicides & insecticides, and solvents.
The Chlorine & Chloramine disinfectant dosed by your water supplier.
Trihalomethanes (carcinogenic chlorine disinfection byproducts) which arise when the chlorine kills organisms in the water.
Sediments and particulate matter to the stated micron rating - usually 20/25 micron.
GAC will also reduce other chemical contaminants but coconut shell activated carbon block is acknowledged as, by far, the superior media and method being effective for the widest spectrum of chemicals including carcinogenic:
PolyChlorinated Biphenyls or PCBs
New PCB contamination is vastly reduced if not eliminated as the regulations for the manufacturing industry ban their use. The problem remains because PCBs are hardy and take years to degrade. PCBs are not free in the water as such but are carried by particulate matter and organics. Removing the matter and organics takes out any PCBs that may be present.
Polycylcic Aromatic Hydrocarbons or PAHs
PAHs are formed naturally in the environment during thermal geological events (eg volcanoes) and natural fires. By far the biggest contributor of PAHs to the environment is the human race. PAHs are formed in all processes involving incomplete combustion of carbon-based fuels, and are therefore emitted during burning of common fuels, such as coal, oil, wood and gas. These settle on land and water and run off the land during wet weather.
Other chemicals
A list would be almost endless and beyond the scope of a web page. Briefly and within context, chemicals can be split into 2 groups: Hydrophilic & Hydrophobic.
Hydrophilic = water loving or soluble and usually attached to the water molecules.
Hydrophobic = water hating or insoluble and carried by the flow of the water.
Happily, common chemicals that may be found in public drinking water and are bad for us are mostly hydrophobic and are readily adsorbed by activated coconut shell carbon.
Top of Page >>
More information below:
Myth: Activated Carbon is effective for Heavy Metals. Hardness (Calcium & Magnesium), Fluoride, Nitrates.
FACT: No it is not. AC will REDUCE these by mechanical filtration but so will a spun or wound Polypropylene1 micron sediment cartridge! The solutions for these need special media cartridges as previously described.
Myth: Activated Carbon is effective for pathogenic micro-organisms - bacteria and Cysts (oocysts); eg cryptosporidium and giardia
FACT: No it is not. AC will REDUCE these by mechanical filtration but so will a spun or wound Polypropylene1 micron sediment cartridge!
Effective filtration is only achieved with a sub-micron (less than 1 micron) cartridge and porous Ceramic is the material of choice with typical micron sizes ranging from 0.5 to 0.9.
However, the Health Protection Agency state "Campylobacter is the commonest reported bacterial cause of infectious intestinal disease in England and Wales. Two species account for the majority of infections: C. jejuni and C. coli. Illness is characterised by severe diarrhoea and abdominal pain....".
The size of Campylobacter is 0.45 micron and will get through a 0.5 micron filter.
Public water supply utilities do not specifically test for Campylobacter.
We make our filter systems 'Pearl-B' & 'Oyster-TBC' with 0.2 micron Ceramic/Carbon Block cartridges for effective removal of pathogenic micro-organisms - including Campylobacter.
Water filters work by having the contaminants 'stick' to the media.
Reverse Osmosis Purifiers use cross-flow filtration down to 0.005 micron and wash the contaminants to waste down your kitchen sink waste pipe (thus returning them to the enviroment).
Neither of these methods 'kill' pathogenic bacteria, viruses, moulds, algae, yeast, and cysts (oocysts) like cryptosporidium and giardia.
For that you need Ultraviolet disinfection where the lamps produce UV-C or "germicidal UV" in the 254 nanometers (nm) region. UV, by itself, is not a filter but is capable of killing microorganisms such as bacteria, viruses, moulds, algae, yeast, and oocysts like cryptosporidium and giardia.
In a nutshell, if it is alive going into the UV chamber, it is lifeless coming out of it.
The Fountain Filters 'Trident' Combination Duplex Filter and Ultra Violet Disinfection System:
1. Pre-Filter with a 5 micron washable sediments cartridge to remove larger particles that could prevent full exposure to the UV light. This is housed in a transparent body for visible evidence of fouling and for deciding when to rinse the cartridge.
2. UV Lamp unit for the kill (Stainless Steel cylinder). Pathogenic bacteria, viruses & micro-organisms including Campylobacter, E.coli, Cysts ( eg cryptosporidium, Giardia...)....
3. Post-UV Filter with a 10 micron (absolute) Carbon Block Filter for Chlorine. Chloramines, Volatile Organic Chemicals (Pesticides, herbicides...) Trihalomethanes, PAHs and particulates(including the dead bodies) down to 5 microns.
What do we recommend?
For straight forward filtration excluding pathogenic micro-organisms The Pearl-T @ £69.30 with a 10 micron coconut shell carbon block cartridge and 9,000 litres life, please click this picture link >> 
To include pathogenic micro-organisms described above:
1. The Pearl-B @ £89.50 with a 0.2 micron ceramic/carbon block cartridge and 9,000 litres cartridge life, please click this picture link >> 
2. The Oyster-TBC duplex system @ £123.90 each with a 10 micron coconut shell carbon block cartridge and a 0.2 micron ceramic/carbon block cartridge with a total of 16,000 litres cartridge life, please use this picture link >> 
A few helpful notes
Filter Cartridge Life:
Neither we nor anyone else can tell you how long a cartridge will last in terms of time. We do not know how many people there are in your household nor do we know how much filtered water you and yours will use for drinking and food preparation.
We express the life span in litres. A rule of thumb is to allow at least 1,500 litres per person per 6 months.
Our page "Cartridge Life Explained" goes into more detail - link at the bottom of this page.
Silver Impregnation
We no longer use silver impregnated cartridges (Silver is classed as a Heavy Metal). The lifespan of silver is short, typically around a month, because as a silver ion reacts with pathogens it is lost - germicidally speaking.
The worst problem was consumer overconfidence leading to inappropriate cartridge replacement regimes.
We prefer to block pathogens with the 0.2 ceramic/carbon block cartridge or render them lifeless with UV.
Multiple Stage Filters
We go as far as 2 stage mixed media filters for Hardness and Heavy metals and balance is the key.
For Fluoride we make a duplex system with activated alumina in the 1st housing and carbon block in the 2nd housing.
More stages than this and the balance is lost as is cartridge life. The more types of media there are crammed into the same space, the less the overall cartridge life.
"Pearl"
We call our simplex drinking water filter range "Pearl" models. We are aware that there are other filters also called Pearl. These are not the same. The Fountain Filters "Pearl" range of models is exclusive to us.
Customised Filter Systems.
The different combinations of all filter cartridge types makes for an impossibly long list of potential filter systems.
We are pleased to offer, on this website, our standard systems which are the most popular.
As a company of water treatment engineers and filter system manufacturers we can alter the systems to a format that suits your needs.
For example; you might prefer the 0.2 ceramic/carbon block cartridge in your Trident UV/Filter. In this case we would take out the coconut shell carbon block cartridge and replace it and adjust the price accordingly.
Top of Page >> Home Page >>
Back to the list of Filters >>
Contact us >>
