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Filters
Trying to decide on which type of filter to
buy?
   There
are three main types of swimming pool filters, D.E.
(which stands for Diatomaceous Earth) {first
filter}, Sand {middle filter} and
Cartridge {last filter}. Different regions of the country seem
to have different preferences; personally my
order would have D.E. first, then Sand, then
cartridge filters. However, the suitability of a
filter to a pool can have more to do with size,
than with type. Always go at least one size
larger than you think you need. Buy the largest
filter you can afford, it's money well spent.
Even
though I have just stated a preference of D.E.
filters over Sand over Cartridge filters, I
would rather have a large cartridge filter
than a small D.E. filter. So remember, in pool
filters, size matters! Many filters installed in
the 70's and 80's were much too small for the
size of pool they filter, and with the
deterioration of age are just barely operating.
All filters at Poolcenter.com are good, solid technology. Major manufacturers try really hard to
produce no "junk." So once again, filter size is more important than brand,
name, type, color, etc.
The
sand in a sand filter (#20 silica sand; 45 - 55
mm) is specially graded to trap particles in the
20 - 100 micron range. As a sand filter collects
dirt, its efficiency increases, trapping more
dirt. When your pressure gauge shows a reading
8 - 10 lbs. over its clean, start-up reading, it
is time to backwash the captured dirt out of the
filter.
"They say" that a sand bed should be replaced
after seven years. Gradual loss of efficiency
may be hard to notice. If your filter requires
frequent backwashing, every week or two, the
sand bed may be "mudballed", or it may be "channeled". It may also "calcify"
with calcium deposits. Other water balance problems may also contribute to sand
deterioration, but a properly sized filter could go over 10 years between sand changes.
Use
of Biguanide chemicals, i.e., Soft Swim or
Baquacil require annual cleaning of the sand to prevent it from "gumming-up".
High amounts of bather oils can gum-up a sand bed. And just the years of a pump forcing
water over the grains wears away the sharp edges of the sand. Such sand becomes more
circular, and traps dirt less efficiently.
Remember that for sparkling water, we need the
trio of sanitation, filtration and
circulation. If one of these areas is lacking,
the water won't look so hot. So, if you've kept
very good chemical maintenance and your
circulation is good, you may have a filter
problem. Is the filter sized properly? Many
filters of the 70's - 80's were grossly
undersized, the trend now in pool filtration is
"Go Big Early."
Adding a small amount of
aluminum sulfate or
"alum", through the skimmer will form a
gelatinous layer on top of the sand bed, useful
in cleaning up an undesirable water condition.
You can also add a small amount of D.E. powder or
other filter media.
"How and When do I Backwash my Sand Filter"
When
the pressure gauge is reading 8 - 10 lbs above the
clean, starting pressure (after backwashing), it
is time to backwash the filter. This process
involves turning a valve so that the water will
flow through the filter backwards, flushing out
the dirt. Hence the name "back-washing." Sand
filters can have either a push-pull valve (also known as
a slide valve) or a multiport valve. The multiport valve has
multi-ports on the valve, usually 6 positions:
-
FILTER: Keep it here 99%, except
when backwashing, rinsing or wasting
-
RINSE: Use this setting for 20 seconds after backwashing to rinse
tank
-
RECIRCULATE: Use this if the filter's broken; at least you're
circulating.
-
BACKWASH: Use this setting to reverse the flow in the filter and send
water out of the waste line. Make sure valves are open or hoses rolled out
-
CLOSED: Put here to close off flow from the pool, usually to work on the
equipment. Do not operate pump with valve in closed position
-
WASTE/DRAIN: Another filter bypass setting, but this
setting sends the water
out of the waste pipe (hose), instead of returning it to the pool.
This setting is used to lower pool
water level or to vacuum to waste.
So, to backwash a sand filter with
a multiport valve;
-
Shut off pump motor
-
Press down on valve handle, rotate valve from FILTER
to BACKWASH position
-
Roll out any backwash hose or open any waste line
valves
-
Open air bleeder assembly on filter, and turn pump
on.
-
Watch pressure gauge for backpressure and hose for
kinks. Be prepared to shut off pump quickly
-
After hose fills with water, run for 2 - 3 minutes or
until water runs clear
-
Shut off pump motor and move multiport
valve handle to RINSE position Run on rinse for 15 - 25 seconds.
-
Shut off pump motor and move multiport valve handle
to FILTER position
-
Turn pump back on and note lower pressure. Roll up
backwash hose
To Backwash a
sand filter
with a
slide
valve;
-
Shut off pump motor, roll out backwash hose (if you
have it)
-
Twist to unlock plunger T-handle, pull / twist
plunger upwards 2 - 3"
-
Open air bleeder assembly on filter, and turn pump on
-
Watch pressure gauge for backpressure (+ 40
PSI) and hose for kinks. Be prepared to shut off pump quickly
-
After hose fills with water, run for
2 - 3 minutes
or until water runs clear
-
Shut off pump motor and push T-handle back down into
locked position
-
Turn pump back on and note lower pressure. Roll up
backwash hose
A
properly sized sand filter should, in most
cases, be able to operate continuously for a
period of 4 weeks between backwashings. A
"Filter Run" of less than 4 weeks may indicate
sand...... (continued........) |
