S.
SESQUICARBONATE Sodium Sesquicarbonate - A chemical
mixture of equal parts of soda ash and sodium bicarbonate
used to increase pH and total alkalinity in pool and spa
water. It has a pH of 10.1.
SAND
This usually refers to the filter medium used by a sand
filter. The grade most often specified by filter
manufacturers is grade No. 20 with a particle size of 45 to
55 mm (millimeters).
SAND
FILTER A filter using sand or sand and gravel as the
filter medium.
SANITIZE
To render sanitary: to kill all living things, including
bacteria and algae. Similar to sterilize.
SCALE
The precipitate that forms on surfaces in contact with water
when the calcium hardness, pH or total alkalinity levels are
too high. Results from chemically unbalanced pool and spa
water. Scale may appear as grey, white or dark streaks on
the plaster, fiberglass or vinyl. It may also appear as a
hard crust around the tile.
SCUM
The extraneous or foreign matter which rises to the surface
of the water and forms a layer or a film there. It can also
be a residue deposited on the tile or walls of the pool or
spa. Sources of scum are soap, oil, deodorant, hair spray,
suntan lotions and others.
SEDIMENT
The solid material settled out from the water.
SEPTUM
That portion of the filter element consisting of cloth, wire
screen or other porous material on which the filter medium
or filter aid is deposited. The nylon grid on a D.E. filter
is the septum.
SEQUESTERING AGENT Also called chelating agent - A
chemical that will combine with dissolved metals in the
water to prevent the metals from coming out of solution
(precipitating or causing stains). May also be a chemical
that removes dissolved metals from water.
SHOCK
TREAT The practice of adding significant amounts of an
oxidizing chemical - (usually non- chlorine oxidizers, such
as sodium per sulfate or potassium peroxymonosulfate) - to
the water to destroy ammonia and nitrogen com- pounds or
swimmer waste.
SHOTCRETE
A mixture of sand and cement sprayed onto contoured and
supported surfaces to build a pool or spa. Plaster is
applied over the shot Crete. Shot Crete is premixed and
pumped wet to the construction site.
SILT
Soil particles having diameters between 0.004 and 0.062 mm
(millimeters). Sometimes they may be too small to be trapped
by the circulation system. In those cases, a clarifier or an
alum product may be needed.
SIMAZINE
A chemical substance used in swimming pools and spas as an
herbicide or algaecide. Mainly used for killing black algae.
SKIMMER
A device installed through the wall of a pool or spa that is
connected to the suction line of the pump that draws water
and floating debris in the water flow from the surface
without causing much flow restriction.
SKIMMER
BASKET A removable, slotted basket or strainer placed in
the skimmer on the suction side of the pump, which is
designed to trap floating debris in the water flow from the
surface without causing much flow restriction.
SKIMMER
WEIR Part of a skimmer that adjusts automatically to
small changes in water level to assure a continuous flow of
water to the skimmer. The small floating "door" on the side
of the skimmer that faces the water over which water flows
on its way to the skimmer. The weir also prevents debris
from floating back into the pool when the pump shuts off.
SLURRY
Water or a liquid containing a high concentration of
suspended solids. Diatomaceous earth (D.E.) is usually added
to the filter as a slurry by mixing a small amount of D.E.
in a bucket of water and then pouring the slurry into the
skimmer with the filter on.
SODA ASH
(Sodium Carbonate) - A chemical used to raise total
alkalinity in pool and spa water with only a slight affect
on the pH.
SODIUM
BICARBONATE (Baking Soda or Bicarb) - A chemical used to
raise total alkalinity in pool and spa water with only a
slight affect on the pH.
SODIUM
BISULFATE (dry acid) - A chemical used to lower the pH
and total alkalinity. 2 1/2 lbs. of dry acid are equal to 1
quart of muriatic acid.
SODIUM
BROMIDE A salt of bromine. It is used to establish a
bromide "bank" in pool and spa water prior to beginning the
use of bromine tablets.
SODIUM
DICKLOR A fast-dissolving, granular, stabilized organic
chlorine compound providing either 56% or 63% available
chlorine. Used for regular as well as super chlorination.
Contains an ingredient (cyanuric acid or stabilizer) that
prevents the chlorine from being destroyed by the
ultraviolet (UV) rays of the sun. Recommended for use in
vinyl- liner, painted or fiberglass pools and acrylic or
fiberglass spas.
SODIUM
HYPOCHLORITE Liquid chlorine. Usually provides 10% to
12% available chlorine; has a pH of 13 and re- quires that
small amounts of acid be added to the pool to neutralize the
high pH. Good for regular chlorination and superchlorin-
ation. Not recommended for spas. Does not contain
conditioner or stabilizer to protect it from sunlight, but
it is protected if stabilizer or conditioner is already in
the water.
SODIUM PER
SULFATE Active ingredient and chemical name of a
non-chlorine shock treatment or non-chlorine oxidizer. Does
not kill bacteria or algae but it will oxidize or destroy
ammonia, nitrogen and swimmer waster. Does not increase
chlorine or bromine levels the way that super chlorination
does, so water may be entered in 15 minutes after addition.
It will not reactivate bromine.
SODIUM
SULFITE A chemical used to neutralize or de-chlorinate
pool and spa water.
SODIUM
THIOSULFATE A chemical used to neutralize or
de-chlorinate pool and spa water.
SOFT WATER
Water that has a very low calcium and magnesium content
(water hardness) - usually means less than 100 ppm or 6
grains. Also water that has gone through a water softerer.
Pools and spas should never be filled with soft water from a
softener. Water with less than 100 ppm of hardness should be
increased to a minimum of 150 to 200 ppm using calcium
chloride.
SOLAR
COVER A cover that, when placed on the water's surface
of a pool, spa or hot tub, increases the water temperature
by absorption and transmission of solar radiation; reduces
evaporation and prevents wind-borne debris from entering the
water.
SOLAR
HEATING SYS. Solar Heating System - It is ussually
panels or coils of plastic or metal through which water
passes to increase the temperature from the sun's radiant
heat.
SOLDIUM
CARBONATE (soda ash) - A chemical used to raise the pH
and total alkalinity in pool and spa water.
SOURCE
WATER Also called "tap" water - It is the water used to
fill or refill the pool or spa.
SPRING
BOARD Also called "diving" board - A recreational
mechanism for entering a swimming pool consisting of a
semi-rigid board that derives its spring from a fulcrum
mounted below the board and attached to the deck.
STABILIZED
CHLORINE A family of chlorine pool sanitizers that
contain conditioner (cyanuric acid or isocyanuric acit) to
protect the chlorine from the degrading UV rays in sunlight.
Most common types are sodium dichlor and trichlor. The
granular form is dichlor which is fact- dissolving and can
be used for regular chlorination or super chlorination by
broad- casting into the pool or spa. Tablet or stick form is
trichlor (which is usually used in a chlorine feeder -
either the floating type or in-line erosion type) used for
regular chlorination only.
STAIN
A discoloration or a colored deposit on the walls or bottom
of a swimming pool or spa. Most often, stains are metals,
such as iron, copper & manganese. They may appear as green,
gray, brown or black. They may even discolor the water.
Sometimes a sequestering agent or chelating agent will
remove them. If not, usually an acid wash is necessary to
remove them from the walls & bottom. The metals get in the
water because the pH was too low or someone has added a
low-pH chemical directly into the circulation system. The
low-pH chemical dissolves a small amount of metal from the
equipment. The metals begin to come out of solutions &
deposit or stain the walls & bottom. Stains are sometimes
confused with scale.
STAIN
INHIBITOR Also called sequestering or chelating agent- A
chemical that will combine with dissolved metals in the
water to prevent the metals from coming out of solution
(precipitating or causing stains). May also be a chemical
that removes dissolved metals from water.
SUPER
CHLORINATION The practice of adding an extra large dose
(5 to 10 ppm) of chlorine to the water to destroy ammonia,
nitrogen and swimmer waste, which can build up in the water.
This level of chlorine is required to destroy all of the
combined chlorine in the water, which is called breakpoint
chlorination.
SURFACTANT
A soluble chemical compound that reduces the surface tension
between two liquids. It is used in many detergents and soapy
cleaning compounds.
SUSPENDED
SOLIDS Insoluble solid particles that either float on
the surface of or are in suspension in the water, causing
turbidity. They may be held in suspension by agitation or
flow. They may be removed by filtration, but if the
particles are too small, they may not be trapped by the
filter. In these cases, a clarifier or alum may be needed to
remove them.
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