Cobalt Bleeding: A condition occasionally present in older fiberglass pools and spas, resulting in dark black spots or blotches forming on underwater surfaces. Stain removal treatments may prove useless or temporary. The most practical remedy is to refinish the pool or spa.
Coping, pool: To maintain a pool's shape and to hold its liner in place, a tile or lip is installed around the edge of the pool. This edge is called coping (also known as edging).
Epoxy Based Refinishing: Refers to materials and processes used to refinish and seal a masonry pool. Such refinishing offers the advantage of strength and durability and reduced interaction between the masonry products in the walls and the pool water chemistry.
Exposed Aggregate Finish: A type of product used as the interior finish in some masonry pools- typically, a mixture of selected aggregates and Portland cement. An acid etching is used to expose some of the aggregates, creating its textured, finished look.
Gorilla Pad: A 1/8-inch-thick geotextile pool floor pad that adds a layer of cushioning to eliminate footprints from forming on the pool floor. It is cut to size and seamed for your pool. No more cutting and taping as with foam. The padding virtually eliminates vinyl pool liner bottom leaks and inhibits weeds from causing holes in the pool liner.
Gunite: A water, sand, and cement mixture that is "gunned" onto the formed shape of a pool interior under construction. After application, a trowel is used on the walls, and a layer of a "plaster" finish is applied over the Gunite. It is this "plaster" layer- most commonly a marble dust Marcite (see separate glossary listing) or an aggregate finish- that will actually contact the water and be visible.
Ladder: A device used to enter or exit a pool.
Laterals: Devices at the bottom of a pool filter that collect the filtered water and carry it up the tank to and back into the pool.
Leaching: A term used to describe the movement of slowly soluble constituents, present in masonry pool finishes, into the pool water. Overall water chemistry governs to what extent any leaching can occur. This normally affects the parameters of pH, total alkalinity, and calcium hardness.
Liner (Vinyl): A vinyl membrane that acts as the container to hold the water in a pool.
Marcite: A finish for Gunite pools that consists of crushed marble and white Portand cement, which forms a watertight layer over the underlying gunite.
Mottling: A term used to describe dark blotches, spots, or stains that appear on some plastered pools. This condition may be caused by the "use and abuse" of calcium chloride in the plastering mixture. There is no solution, short of refinishing, if mottling occurs. Algae and metal stains are other possibilities.
Plaster: A type of finish that is applied over the concrete shell of an in-ground pool. Typically, it is a mixture of cement and aggregate used as an interior finish on concrete pools or spas.
Pool, above-ground: A home pool that is built on top of the ground, constructed of various materials including a vinyl liner to contain the water.
Pool, in-ground, fiberglass: A pool that is built into the ground, with fiberglass as the material of construction. This type of pool is not very flexible in terms of size and shape.
Pool, in-ground, Gunite: A pool built into the ground- usually level with the surface- and constructed with a concrete shell that is "gunned" on (hence the name gunite). The surface can be finished with plaster or aggregate materials. This type of pool is very flexible in terms of size and shape.
Pool, in-ground, vinyl: A pool that is built into the ground- usually level with the surface- and constructed from various structural materials such as aluminum, steel, polymer plastic, and wood. This type of pool has a vinyl liner, and is very flexible in terms of size and shape.
Pool, on-ground, residential:A removable pool that is on the ground and also has an excavated area below the earth.
Pool, permanent: A pool that cannot be readily disassembled, usually used to describe an in-ground pool.
Precipitation: The formation of an insoluble chemical compound, thereby causing it to drop out of solution. Changes in the water analysis parameters of pH, total alkalinity, and calcium hardness can cause precipitation. Not treating dissolved minerals, such as iron, can lead to precipitation, and resulting staining and discoloration problems. Precipitation of calcium can lead to cloudy/hazy pool or spa water or scale deposit problems on underwater surfaces.
Quartz: A commonly used ingredient in quartz-aggregate finishes. Quartz or silicon dioxide is more chemical-resistant and durable than the more traditional marble dust additives.
Top rail: The outer edge of an above-ground pool, normally specified in 6", 8" or 9" sizes
Underdrain: The lower collection system in a filter that directs filtered water back toward the pool. It also distributes pool water in reverse during backwashing (see Laterals).
Vinyl Liners: Placed inside the formed shape of a pool, vinyl liners are made of a heavy-gauge vinyl. They are used to contain the water within the inner surfaces of the walls and bottom. Vinyl liners are chemically inert, and enable the use of various materials as pool walls. Available in a variety of colors and patterns, vinyl liners come in stock sizes and custom sizes.
Wading pool: A pool with a shallow depth.