A I B I Bre I C I Chl I Cya I D I E I F I Flo I G I H I I I J 

L I M I N I O I P I Q I R I S I Sta I T I U I V I Vol I W I Z

RATE OF FLOW:  Quantity of water flowing past a designated point within a specified time period, measured in gallons per minute (gpm).

REAGENT:  The chemical indicators used in testing water balance. (All the little bottles or tablets in your test kit).

RE-BAR:  Reinforcement bar, used to add strength to a concrete. After excavation of an in ground pool, a steel cage is formed out of re-bar, and the gunite shell is shot over and surrounding it.

RESIDUAL:  Usually refers to free available chlorine levels remaining in the pool after initial treatment or activity with contaminants.

RESTRICTED FLOW:  The term used to describe a condition preventing full flow of water. Restriction can occur with full skimmer or strainer baskets, obstructions in the plumbing, dirty filter, undersized plumbing or equipment , or placing devices like, heaters, cleaners or fountains in the circulation system. Restriction on the suction side creates higher vacuum, (or suction) while on the pressure side creates higher pressure.
 

SAND FILTER:  A filter tank, usually fiberglass or ABS plastic, filled with sand and gravel. The pump diffuses water over the top of the sand bed, and forces it through the sand and into the laterals on the bottom.

SANITIZER:  A chemical agent used to remove unwanted contaminants.

SCALE:  Usually whitish in color, scale forms on pool surfaces and equipment when mineral salts are forced out of solution. A scaling condition is one in which calcium hardness, pH and/or alkalinity levels are out of balance.

SEQUESTERING AGENT:  A sequestering agent ties-up minerals tightly in solution, preventing their precipitation, which colors the water and/or stains the pool. Synonymous to chelators, these are commonly called stain & scale chemicals.

SKIMMER:  A surface skimmer is a plumbing fitting set at water level, containing a weir mechanism and a debris basket. The skimmer is part of the suction side circulation system.

SHOCK:  As a noun it loosely describes the products used in shocking, such as hypochlorites, potassium permonysulfate or hydrogen peroxide. As a verb it describes the act of bringing the sanitizer level up so high that breakpoint chlorination is reached. When breakpoint is reached, a "shock" or perhaps a "lightning bolt" is a better analogy, is sent through the water, tearing apart molecules and slashing through cell walls. Ultimate purification, man.

SHOTCRETE:  A different type of application of the concrete and sand mix which is used to "shoot the shell". Gunite is pumped dry and mixed with water at the gun, whereas shotcrete is pumped wet.

SNOWBELT: The northern half of the United States where freezing temperatures are particularly common.

SODA ASH:  A base, used to counteract an acidic condition by raising pH.

SODIUM BICARBONATE (baking soda):  Another base, however its properties will increase alkalinity more than pH. Used to raise Total Alkalinity levels.

SODIUM BISULFATE:  An granular form of acid, used to counteract a scaling condition by lowering pH and/or alkalinity.

SODIUM HYPOCHLORITE:  Liquid chlorine used in pools, identical yet stronger than Clorox bleach.

SODIUM TETRABORATE:  New technology that renders algae incapable of processing carbon dioxide, which they need to live.

SODIUM DICHLOR:  A granular form of chlorine that is stabilized with cyanuric acid. Used for shocking and super-chlorination.