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Water Filters – Fleck Duplex

You are here : Home | Products & Systems | Water Filters | Fleck Water Filters | Fleck Duplex

Water Filters –  Fleck Duplex Range


Water Filters – Fleck Duplex

The Fleck Water Filter Units are suitable for commercial, industrial and residential applications. All of our systems are either Time Clock or meter controlled.

We supply Simplex, Duplex, Triplex and bespoke water filter systems.

Fleck Duplex systems are designed to produce a continuous and uninterrupted supply of filtered water 24/7. These systems have a twin tank that work alternately so that there can always be one tank in service. These systems are particularly useful for industrial or commercial applications.


Fleck Duplex Water Softener Information

Fleck Duplex Water Filtration Systems

Fleck Duplex systems are available in flow rates of between 1.2 – 29.0 m3 per hour. Fleck systems are notoriously simple and easy to use and assemble. They are also very simplistic in their technology having only one moving part (a single piston) making them easy to maintain and making the likelihood of failure very low. These systems are also recognised for being affordable with a large product range. All of these systems spares parts and consumables are available at online Industrial Water Equipment.

All of our Fleck Duplex water filters comprise of :

2 x vessel and riser tubes + filled with selected medias (size dependant on your water flow)

1 x Fleck valve (either time clock or meter controlled)

All of our filtration systems are available in both time clock and meter controlled. These systems are both effective but do have individual features that can make them more suited to certain applications and settings.

Timer controlled systems are relatively inexpensive. The technology behind it is very simple, the timer allows you to manually set when you would like the system to kick-start the regeneration process. This timer can be set for when you are less likely to require filtered water (as standard, the timer is set for 2am).

Timer controlled systems are simple but effective and are widely used for numerous different applications the world over. They are ideally used on systems that do not require water treatment 24/7 and whereby the flow rate is within range to ensure the media does not reach the point of exhaustion before the regeneration process kicks in. In duplex systems, once one vessel has been exhausted, the second then comes into service.

Another option for a more specific regeneration is a meter controlled valve. These valves allow you to pre-set a specific volume of permeate flow that can will pass through the system before the valve will kick in to the regeneration process. The volume of water that can pass through will depend on the media type and the volume of the vessel and media within the vessel. Meter controlled systems almost eliminate all water wastage and when used with a water softening, also prevents unnecessary salt wastage and being sent to drain. For large scale industrial productions, a meter controlled valve is often favoured.

Medias available for Fleck Duplex systems are as follows :

Activated Carbon

Activated Carbon is primarily used for the quick and effective removal of colour, taste and odour. Another common use for activated carbon is for use as part of pre-filtration before Reverse Osmosis systems. Reverse osmosis Systems, particularly the membranes are highly sensitive to chlorine which can be a problem as most water sources come directly or indirectly from mains water that is dosed with chlorine. If chlorine comes into contact with Reverse Osmosis membranes, they will become irreversibly damaged and will require replacement.

Other contaminants Activated Carbon is commonly used to filter are Ozone, metals, organics and a large range of different chemicals.

Activated carbon has numerous different origins and each ‘type’ of activated carbon has different characteristics which makes it more suited to certain applications. These origins include coconut shell, Bone char, wood, peat and petroleum based residue.

Multi Media Filtration (MMF)

Multi Media Filtration (MMF) is a combination of four different medias starting with a larger more course gravel and working down to a fine sand and anthracite coal. These filters are ideal for the reduction of suspended solids (turbidity) down to as little as 5 microns with assistance from a coagulant. Again, these systems are commonly used as a pre-treatment for a more robust water treatment system such as reverse osmosis.

The four media layers of a MMF are as follows :

Media 1 is a course gravel and is placed at the bottom as it is the heaviest and largest particle this layer is used as a support layer and to remove large suspended solids.

Media 2 is a 2mm filter sand/ garnet and is placed directly underneath the finer layer of sand.

Media 3 is a fine filter sand/ garnet and is placed directly underneath the anthracite.

Media 4 consists of Anthracite (coal) and although it is the largest particle, it is also the lightest and it therefore placed on top

The media within the filter is arranged in this way to ensure larger particles are removed at the beginning allowing for finer particles to pass through and be removed by the following layers of media.

Filox R 

The main component of this substance is Manganese Dioxide (80%) this high level of Manganese Dioxide makes it the most effective on the market at removing Iron, Manganese and Hydrogen Sulphide. Filox R is often more expensive that comparable medias but its effectiveness does in fact make it the most economical option. Another advantage to Filox R is that it requires no chemical assistance therefore no requirement for chemicals to be stored on site.

Filox R is capable of removing the following contaminants without any further chemical interventions to the according levels.

  • Manganese  3.0ppm
  • Iron 15.0ppm
  • Hydrogen Sulphide 7.0ppm

If higher levels of removal are required, additional treatments are available such as oxidising agents, chemical regeneration or tannin removal.

pH Correction Media

pH Correction Media is commonly used when the permeate doesn’t come directly or indirectly form mains water. Water from borehole or natural spring for example does not have a pH within the ideal range o f 6.5 – 9.5. levels that are out by just 0.1 either way can have a huge effect of the quality of the water particular when used within industry of food and beverage production lines. An unbalanced pH can also have a detrimental and corrosive effect on internal pipework’s and plumbing as well as boiler and water treatment systems. The media used fro pH correction is Limestone. Limestone is made up from Calcium and Manganese salts, these minerals dissolve into the water increasing the level of the pH. Regular top ups of the limestone will be required but this is a very simple process as the limestone is safe and easy to handle.


Birm is commonly used for the removal of Iron and manganese but also has the capabilities of removing a large range of chemicals and contaminants such as radium, arsenic and Hydrogen to name a few. Birm is a very resilient material and the process of filtration doesn’t erode the media. Because of this, top ups are rarely required making this media highly economical and easy to work with. Birm is another substance that does not require the use of chemicals for it to reach its full potential making it a favourable option for all settings.

Nitrate Removal

Nitrate Removal is very similar to the water softening process using ion exchange resin. Nitrate removal instead used a different polymer resin that is specifically targeted to attract sulphates and nitrates and to replace them with chloride ions. Once the bed has been exhausted within the first column, the system will then kick into regeneration and in a duplex system, the second columns will then come into service. Nitrates can be particularly harmful in ingested to babies, young children, the elderly and for those who’s immune system has been compromised. Nitrates can be difficult to detect in water as it colourless, tasteless and odourless. Consuming Nitrates can cause a condition known as Methemoglobinemia or sometimes referred to as blue baby syndrome. This condition is most serious if left untreated for infants 6 months and under and can be fatal.