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TYPES/Pre Filters

What are Pre Filters / Sediment?

Pre-filters - aka sediment filters - are typically used in complex water filter systems such as Ultra Violet treatment or Reverse Osmosis.

Pre-filters / sediment filters can be used either "pre" or "post" other water filters ie in front of, or after, another filter.

Either way they stop particles / sediment getting any further up the line.

("Pre filter is the default industry term which is why we favour it here).


How They Work

Pre filters catch larger particles in the water in stages and prevent the main filter becoming blocked and slowing the flow.

For example a typical pre-filter configuration could be: first in line is a 50 micron pre filter - this catches anything larger than 50 microns. Next in line is a 20 micron filter, followed by a 5 micron filter... and so on.

(To give you an idea, a human hair is 100 microns in diameter. 5 microns is usually as much as you need to filter for UK water - unless you are on a non mains water supply and want to filter out dangerous protozoa like cryptosporidium

Without pre-filters, the life of the main filter would be much shorter.

Flow rates will depend on the incoming water pressure and the age of the filter.

Flow will reduce as the cartdridge fills with trapped particles. A slowed flow rate is often the indication that it's time to change the cartridge.

There are 3 main types of prefilters

Polypropylene (PP) Water filters

These have updated traditional string and pleated filters. - see below.

They are a better technology, outperforming the old types and are lighter to transport.

PP filters are excellent at holding in contaminants while allowing for high flow rates.

We sell these in the following standard sizes. (Click the link to see micron filtration available for each type.)

Ten Inch Slimline Prefilters
Ten Inch Jumbo / Wide Prefilters
Twenty Inch Slimline Prefilters
Twenty Inch Jumbo / Wide Prefilters

The older traditional pre filters are:

Pleated Water  Filters

These look like folded paper and are more popular than string types see below.

The folds give Pleated Filters a much better depth in surface area. eg they have a 2.5 bigger surface area than PP. This makes them last longer and perform well - they will typically last about 2x as long at opt performance. (Here's a picture of a pleated filter).

We dont supply pleated filters becuase overall the new technology polypropolene filters (see above) out-perform them. You can easily swap out your old filter for an equivalent polypropolene filter.

String Water Filters

These are made by winding string around a core. They used to be very widely used but have been replaced by PP filters  see above

People who already have a string filter will naturally want to replace like for like. But cannier users also know they can wash the string. They shouldn't really do this but people like to save a few pennies here and there. Washing makes the string filter last longer. But it's not really worth the effort.

We dont supply string filters becuase overall the new technology polypropolene filters (see above) out-perform them. You can easily swap out your old string filter for an equivalent polypropolene filter.