Filters remove both visible debris and microscopic matter. When your
chlorine has exhausted its work, the filter steps in and performs the
job of removing the now dead organisms. Periodically filters require
backwashing to remove accumulated debris. Your filter manufacturer will
specify the method and frequency of backwashing, although typically it
is recommended when water pressure in your filter is 8 - 10 pounds
above the standard operating pressure.
There are three basic types of filters. Each have advantages and
- Diatomaceous earth. Also known as a DE filter. These filters have
a filtration range of 1-3 microns. This is substantially smaller than
any of the other filter types and is therefore generally viewed as
superior. Diatomaceous earth is actually a porous powder formed form
the fossilized exoskeletons of tiny diatoms ( like plankton - yuk !) .
Clean water can pass through the small openings in the powder but
debris and most micro organisms can not. All of these filters have
internal elements that become coated with the DE 'filter cake". As with
a sand filter, a DE filter must be periodically backwashed and
recharged with additional DE.
- A sand filter is
probably the most common type of filter. it has a filtration range of
20 - 40 microns. It is also the least expensive type of filter. You
must use a special type of sand in these filters that is typically pool
grade #20 silica sand, but check your manufacturer to match the exact
specification. . Like a DE filter, periodic backwash and recharging of
the filter is necessary.Typically this is done every few weeks.
- A cartridge filter is in the mid range of both performance and
price when compared to the two previous methods. The filtration range
is 10-20 microns and therefore the performance is superior to sand but
inferior to DE. A cartridge filter does not require backwash. Instead
you either replace the filter and/or clean the filter periodically by
removing it from the housing and using a high pressure garden hose.
usually this is done about once or twice season. Cartridge
filters have greater surface area that results in fewer clogs, lower
maintenance and reduced operating pressure with therefore less back
pressure on the pump. this leads to greater flow, higher turnover and
The eFamilyFun section of pumps and filters can
be seen here.