BACKFLOW The backing up of water through a
pipe in the direction opposite to normal flow.
BACKWASH The process of thoroughly cleaning
the filter by reversing the flow of water through it with the dirt and rinse
water going to waste.
(chemical related) Single-celled
microorganisms of various forms, some of which are undesirable or potentially
disease-causing. Bacteria are controlled by chlorine, bromine or other
sanitizing and disinfecting agents.
A chemical or element that kills, destroys or
controls bacteria such as Chlorine. Silver algaecides are actually bactericidal,
and are useful on "pink algae".
Chemically called sodium bicarbonate. It is white
powder used to raise the total alkalinity of pool or spa water without having
much affect on pH.
The correct ratio of mineral content and pH level
that prevents the water from being corrosive or scale forming.
BALL VALVE A simple non-return valve
consisting of a ball resting on a cylindrical seat within a liquid passageway.
(chemical related) Also called basic - A
class of compounds which will react with an acid to give a salt. Base is the
opposite of an acid. Common bases used in pools include soda ash, sodium
bicarbonate, and sodium carbonate. See alkali.
(chemical related) The amount of base (or pH
increaser) water needs to reach the proper pH range. For example, to raise pH
from 7.2 to 7.6, a pool may "demand" 2 cups of soda ash. The actual amount
depends on pool volume and other factors. Some test kits contain the titration
test used to determine base demand.
The number of people in the pool or spa
at any given moment, or during any stated period of time. Bather load also is
affected by lotions, deodorants, perfumes, etc.
see "sodium bicarbonate"
(chemical related) Biguanide is an
abbreviated name for polyhexamethylene biguanide hydrchoride (PHMB), an
alternative to using chlorine or bromine as a sanitizer. It is a non-chlorine
liquid chemical and is highly incompatible with chlorine, bromine, metals and
some other common pool chemicals. It is used along with an additional product
containing Hydrogen Peroxide which is used to oxidize the swimming pool water.
The procedure for using biguanide as a sanitizer is commonly called 'biguanide
system'. Some examples of 'biguanine systems' are Baquacil, Softswim and Clear
BLACK ALGAE A type of algae that grows on
pool walls and floors as dark spots. Colonies usually form in areas with less
circulation. Black algae feels slimy and can be brushed off with some effort.
The algae embeds itself into porous pool surfaces and can be difficult to
(chemical related) This term usually refers
to liquid chlorine (sodium hypochlorite 12% available chlorine). It is the same
chemical used in laundry bleach but pool chlorine is 12% available chlorine
while laundry bleach is about 5 to 6%% available chlorine.
BLOWER An electrical device that produces a
continuous rush of air to create the optimal bubbling effect in a spa, hot tub
or whirl- pool. It is usually plumbed in with the hydrotherapy jets or to a
separate bubbler ring.
A condition caused by too much copper in the pool
water. Blue fingernails are not caused by chlorine. The copper may get into the
water by the bad practice of placing trichlor tabs in the skimmer. This acidic
product will cause low-pH water, which will in turn dissolve metals in the
equipment. The dissolved metal (usually copper) then stains hair, fingernails
and, eventually, pool walls. It can also be caused by keeping the pH too low or
The application of a large dose of chlorine intended
to reach the point where free chlorine, measured in ppm, is at a high enough
level to break apart molecular bonds, specifically the combined chlorine
molecules. When this point is reached with sufficient addition of chlorine,
undesirable compounds responsible for odors, eye burn, irritation and poor
sanitizing in the pool are oxidized. All chlorine added after that point is free
By-products formed when bromine reacts with swimmer
waste (perspiration or urine), nitrogen or fertilizer. Bromamines are active
disinfectants and do not smell, although high levels are body irritants.
Bromamines are removed by super chlorination or shock treating.
(chemical related) A common term for a
bromide salt used to supply bromide ions to the water so they may be oxidized or
changed into hypobromous acid, the killing form of bromine. Used as a
A mechanical or electrical device for dispensing
bromine at a controlled rate. Most often a canister or floater filled with
tablets of bromine.
(chemical related) A common name for a
chemical compound containing bromine that is used as a disinfectant to destroy
bacteria and algae in swimming pools and spas. Available as a tablet or as
sodium bromide, a granular salt.
BTU Abbreviation for British Thermal Unit.
The amount of heat necessary to raise 1 lb. of water 1 degree Fahrenheit.
(chemical related) A substance or compound
that stabilizes the pH value of a solution. It is also the water's resistance to
change in pH.
(chemical related) The ability of the pool
water to resist changes in pH. If pH bounces, or resumes unwanted levels soon
after adjustment, the buffering capacity is too low and a buffer or pH locking
product should be used.
BYPASS An arrangement of pipes, gates and
valves by which the flow of water may be passed around a piece of equipment or
diverted to another piece of equipment; a controlled diversion.