FOUNTAINS & SWIMMING POOLS - 4
Water supply
There are three general systems for handling
the water requirements of small swimming
pools. The most
common one, called "fill and draw," is
the system of filling the pool,
using it for an interval of time, ther
draining it and refilling. Some
owners vary the scheme by not draining
completely but drawing the
water down so that a thousand or so gallons
can be added. Disadvantages of this scheme
are that the water grows progressively
dirty, draining and refilling are likely
to be neglected, and a schedule
of draining and refilling which is based
primarily on time does not
take into account the possibility of
severe contamination of the water
in the pool occurring at the start of
the cycle. In spite of its faults,
this is the system which is used for
most small private pools. The
initial installation costs very little
for most pools supplied this way
are simply filled with a hose. Everything
considered, it is the best system when
water is available at low rates and when
restrictions are
not clamped on the use of water during
the swimming season.
The second scheme is called "flow
through" because water enters
constantly and drains away constantly.
The pool is emptied only
when it is necessary to scrub down the
sides and bottom, usually not
more than twice a season. For small pools
the rate of flow need not
be great, and often is as low as 3 gallons
a minute. Springs, flowing
artesian wells, and brooks are good sources
of supply for flow
through pools. The plumbing required
is simple and adds little to
the cost of the pool.
The third system is similar to what
is required by law for public
swimming pools in many localities. This
is a re-circulating system
with provisions for filtering and disinfecting.
Pools which get only
average use need be filled only once
a season. The original water is
used over and over again and water is
added only to make up the
loss due to evaporation. An adequate
re-circulating system can cost
$1000 or more, and there are other disadvantages.
The chlorine
used for disinfection of the water is
irritating to eyes and nose. In
climates where summer temperatures are
hot for considerable periods,
the water in the pool may become uncomfortably
warm. The sys-
tem requires a pump and motor, and, therefore,
the purchase of a
moderate amount of power.
Water inlets are required with both
the flow-through and re-
circulating systems. The best location
is at the shallow end of the
pool about 1 ft. below the water line.
Two inlets rather than one
are recommended in order to obtain good
distribution of the fresh
water. Large pools are sometimes equipped
with more elaborate sys-
tems of inlets which are designed so
as to distribute the fresh water
immediately throughout the pool, but
this is not an important con-
sideration in small private pools.
The average homeowner has little opportunity
for choice among
these systems. If his property is located
where a dependable supply
or pure flowing water can be tapped,
the flow-through system will
be adopted naturally. Lacking a flowing
water supply, the next best
bet is a fill-and-draw system. However,
if the price of water or other
considerations make this scheme unfeasible,
equipment for filtering,
disinfecting, and re-circulating must
be included in the plans for
the pool.
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