Hot Tub Terms: Things You Should Know if You Own a Spa

Words and Terms To Know if You Own a Spa or Hot Tub

people in hot tub in snow
Hot tubbing in the snow. Chris Clinton/Getty Images

Owning a hot tub or spa means you'll need to know the terminology and lingo that accompanies it, whether you maintain it yourself or hire a professional. 

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    Welcome to the World of Spas and Hot Tubs

    hot tub with view
    A hot tub with a view. Kelly Funk/Getty Images

    Consult this handy glossary as a quick reference tool. If a word or term is missing, contact us on social media and it will be added.

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     A dry or liquid chemical that lowers pH when added to water.

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    Air Switch

    A pneumatic-mechanical control devce that is used to safely operate spa and hot tub equipment. To operate, a button that is located in or near the water is depressed, sending air pressure along a hose to an on/off switch. 

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     The characteristic of water tht registers a pH above neutral.

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    Aluminum Sulfate

    An additive for sand filters that helps prevent sand from combining and hardening; thus, not filtering impurities from water.

     

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    Bather

    Any person using a spa or hot tub. Hopefully, not to take an actual bath with soap and shampoo, but for relaxation or as hydrotherapy.

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    Bromine

    A sanitizer similar to chlorine and one of the original hot tub sanitizers.

     

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    Biguanide

    A sanitizer which is part of a water treatment system. 

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    Cedar

    Aromatic, attractive wood sometimes used to finish the hot tub exterior cabinet. 

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    Digital Programming

    Popular controls used to manage such features as water temperature, filtering cycles, light and even accessories such as stereo and TV. 

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    Fiberglass

    A material shaped to form hot tub shells.

     

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    Fiber Optics

     Lighting system in which light is generated at a remote source and transmitted along fibers. 

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    Filter

    A porous, fibrous material in cylinder form that’s called an element. It allows water to pass through while it collects particles, organic matter, oils, lotions and foreign debris that accumulates in hot tub water.

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    Filter Cycle

    A programmed period of time the hot tub filters water each day. Also refers to the length of time between cleaning and replacing the filter element.

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    Flow Monitor

    Gauges how fast and how much water is flowing. 

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    Flow Rate

    The measure of how many gallons per minute pass through a hot tub pump. A better measure of water movement than pump horsepower.

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    Foam

    Frothy bubbles that sometimes form on the hot tub water surface. Also, a polymer-based insulating material sprayed or cemented on the underside of the hot tub shell to slow heat from escaping through the shell.

     

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    Heater

    The method in which hot tub water is warmed electrically. Some custom hot tubs have gas heaters.

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    Hydrotherapy

    Pertaining to hot tubs and spas: the external use of warm or hot water to treat diseases and ailment. Hydrotherapy is used for conditions ranging from stress to sore or strained muscles and arthritis. Jets that move the water, along with the warmth, help in treatment.

     

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    Insulation

    A polymer-based foam-like material placed between the hot tub shell and the air around the shell essential that works against heat loss, muffles sounds of pump operation, conserves energy and sometimes strengthens the shell.

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    Jets

    The openings through which water flows into the hot tub. Jets affect the direction, volume and velocity of water. 

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    Lighting

    Can be arranged around the perimeter, underwater and other various ways to create atmosphere and allow reading in the hot tub. 

     

     

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    Main Drain

    An exit for water from the hot tub, usually at the lowest point in the hot tub shell.

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    Ozonator

    A device that assists in disinfection. 

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    pH or Potential Hydrogen

    A measure of how acidic or base the water is. A pH of 7.0 is neutral. Below 7.0 is acidic. Hot tub water should be kept slightly base (alkaline) with a pH of between 7.2 and 7.6.

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    Polyethylene

    A plastic used to make some hot tub cabinets. 

     

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    PPM

    Parts per million.  A measure of the quantity of a chemical present in hot tub water.  

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    Priming

    Starting a flow of water to a pump so it won’t suck air. Pump: Moves water through the filter and heater system and back into the hot tub. Pumps either push or pull water through the filter.

     

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    Reagent

    A dry or liquid chemical that has been formulated for water testing. An agent or substance that reacts to another known agent, producing a predictable color.

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    Sand Filter

     A filter that uses sand to collect debris from water running through it. 

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    Sanitizer

    A chemical compound that oxidizes organic material and bacteria to provide a clean, bacteria-free water environment.

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    Shell

    The container of a hot tub or spa that holds water and bathers or soakers.

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    Shock Treatment

     Also known as: Superchlorination or shocking

    Application of extremely high levels of chlorine to completely oxidize any organic material in a hot tub or spa and leave a substantial chlorine residual. This procedure is performed to sanitize elements in water that might resist normal chlorination.

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    Skimmer

    A part of the circulation system that removes debris from the surface of the spa watear by drawing surface water through it.

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    Soaker

    A person who is soaking in the spa or hot tub, presumably to reap the benefits of the hot water and circulation. See bather.

     

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    Stainless Steel

    A material used in building hot tubs and spas that is resistant to staining from minerals. Most grades resist rusting. 

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    Strainer Basket

    A plastic mesh container that strains debris from water flowing through it inside the strainer pot.

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    Temperature, Ambient

     The average surrounding temperature.

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    Thermostat

    Part of the heater control circuit. Adjustable, this device senses temperature and can be set to break the circuit when a certain temperature is reached. It then closes the circuit when the temperature falls below that level. 

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    Time Clock

    Aka timer: An electromechanical device that automatically turns something on or off at preset intervals.

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    Total Alkalinity

    A measure of the stability of pH. 

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    Urethane Foam

    An insulating plastic used in some hot tubs to protect against heat loss and reinforce the surface to provide support.

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    Valve

    A plumbing device that controls the flow of water.

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    Weir

    A barrier in a skimmer over which water flows. The floating type raises and lowers its level to match the water level in the spa, while another type floats up and down inside the skimmer basket.