Alkalinity: How alkaline is measured in spa water, i.e. above 7.0 pH.

Alum: Aluminum sulfate, commonly called floc, is used to help clarify water.

Calcium Chloride: Added to raise calcium hardness.

Calcium Hardness: A measure of the level of [...]]]> Algae: Small plant life which rarely grows in spa water. Often green, yellow or black, algae is slimy in texture.

Alkalinity: How alkaline is measured in spa water, i.e. above 7.0 pH.

Alum: Aluminum sulfate, commonly called floc, is used to help clarify water.

Calcium Chloride: Added to raise calcium hardness.

Calcium Hardness: A measure of the level of calcium salts in the water. Helps determine how scaling or corrosive the water is.

Chlorinator: A canister which releases chlorine into the water.

Chlorine: A sanitizer and an oxidizer. As a sanitizier, kills bacteria; as an oxidizer burns off organic matter and kills algae.

Clarifier: Chemical used to remove cloudiness from water.

Disinfectant: A chemical that kills bacteria and deodorizes.

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 spa water. 

Filter Cycle: A programmed period of time the spa filters water each day. 

Humidity: In excess is associated with mildew, especially on indoor hot tubs where moisture tends to be trapped in the hot tub room.

Hydrogen Peroxide: A non-chlorine oxidizer used with biguanide systems.

Ionizer: A device that generates copper and/or zinc and/or silver ions to kill bacteria and algae.

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

Oxidizer: Chemical that burns up organic matter.

Pump: Moves water through the filter and heater system and back into the spa.  

Sanitizer: A chemical used to kill bacteria.

Shock: The action of adding a chemical known as an oxidizer to spa water to gas-off organic wastes which cause cloudiness and algae.

Skimmer: A box-like compartment in the spa through which debris, oily film and contaminants flow into the filter when the pump is on.

Strainer: A basket in some spa pumps that collects debris which could restrict water flow.