Meaning that tools are required to alter or remove portions of the equipment.
TANNIN
Any of a group of water soluble, natural organic phenolic compounds that are produced by metabolism in trees and plants and are part of the degradation-resistant fulvic acid materials formed during the decomposition of vegetation. Tannins occur in water or in almost any location where large quantities of vegetation have decayed. Tannins can impart a faintly yellowish to brown color to water. Tannin molecules tend to form anions in water above pH 6 and can be treated with anion exchange resins. Below pH 5, tannins are better treated with activated carbon.
TASTE AND ODOR
A type of filter that makes water smell and taste better.
TDH
Total Dynamic Head
TDSL
Total Dynamic Suction Lift
TEFC
Totally Enclosed Fan Cooled - a type of motor enclosure
THIN FILM COMPOSITE
A membrane made with a polyamide-based polymer consisting of three layers: a polyester support web, a micro porous polysulfonic inter layer, and an ultra-thin barrier coating on the top surface.
TITRATABLE ALKALINITY
The quantity of hydrogen ions (H+), which must be added to a sample of alkaline water in order to establish a condition of neutrality.
TORQUE
A twisting or turning effort that results from a force being applied to a rigid object at a radial distance from the center of rotation.
TOTAL DISCHARGE HEAD
The total pressure or head the pump must develop on the discharge side. It is the sum of THE ELEVATION, THE SERVICE PRESSURE, and THE FRICTION LOSS. Of course, all of these measurements must be expressed in the same units, usually feet of head, before adding them together.
TOTAL DISSOLVED SOLIDS
The sum of all ions in a solution, often approximated by means of electrical conductivity or resistance measurements. Total dissolved solids (TDS) measurements are commonly used to assess distiller and reverse osmosis unit performance. It is important to note that a test measuring the electrical conductivity of the water sample provides only an estimate of the TDS present, as conductivity is not precisely proportional to the weight of an ion and nonconductive substances cannot be measured by electrical tests.
TOTAL ORGANIC CARBON
A measurement of the total mass of dissolved carbon in a water sample, excluding that originating from carbon dioxide and carbonates.
TOTAL SUSPENDED SOLIDS
The particles, which can be removed from a solution by filtration, usually specified as the matter which will not pass through a 0.45 micron pore-diameter filter.
TOXIC
Meaning that a given substance has an adverse physiological affect on man.
TREAD CONTACT SURFACE
Foot contact surfaces of a ladder, step, stair or ramp.
TREADS, RECESSED
A series of vertically spaced cavities in the pool, spa or hot tub wall creating tread areas for step-holes.
TURBIDITY
A measurement of the amount of suspended solids (colloids) in a solution. Caused by stirred-up sediment, silt, clay, etc. Turbidity blocks light rays and makes the water opaque. Turbidity is measured in nephelometric turbidity units (NTU). Potable water should not exceed 0.3 NTU. Turbidity cannot be directly equated to suspended solids because white particles reflect more light than dark-colored particles and many small particles will reflect more light than an equivalent large particle.
TURNOVER
The period of time (usually in hours) required to circulate a volume of water equal to the pool, spa or hot tub capacity.