Do Pool Chemicals Expire? Average Pool Chemicals Shelf Life

Maintaining chemicals in conditions that are constantly cold, dry, and dark will prolong their use. Pool owners and operators who know how and where to store chemicals and other pool items may preserve their chemicals securely and save money.

Chlorine

As with any chemical, chlorine tablets may deteriorate if left for too long or incorrectly kept. However, if stored properly, they may stay functional for more than five years. Knowing how to properly store chlorine tablets will guarantee that any tablets left over at the end of the summer swimming season will still be effective in the spring.

Tablets of chlorine are the most prevalent kind of pool chemical. They are available as 1-inch and 3-inch tablets, as well as 3-inch sticks. They are individually wrapped in plastic, which further slows decomposition, and contain 90% chlorine. However, there is no way to tell how stable they are just by looking at them.

Chlorine tablets have the longest shelf life compared to all other chlorine-based pool products. Three years after being maintained between 50 and 70 degrees Fahrenheit (10 and 21 degrees Celsius), chlorine tablets may retain up to 98% of their initial chlorine concentration if kept between 50 and 70 degrees Fahrenheit (10 and 21 degrees Celsius). Chlorine-based chemicals are more stable when stored in a tightly sealed bucket kept in a cool, dry, and well-ventilated environment.

Granular chlorine – when kept in airtight containers that are cool and dry can last for over five years, whereas when stored improperly and exposed to humidity it can dissolve in less than two years.

Liquid Chlorine – (sodium hypochlorite) is the most unstable pool chemical, losing 50% of its potency within the first six months and 90% after a year; when exposed to extremely hot or cold temperatures, or sunlight, it degrades even faster.

Algaecides

If it is kept in a location that is cool, dry, and indoors, it can maintain its effectiveness for up to five years. However, exposure to direct sunlight and temperatures above 75 degrees Fahrenheit (24 degrees Celsius) will shorten its shelf life, and temperatures at or below freezing can render it ineffective.

This product is specially formulated to eliminate cloudy water due to accumulations of yellow or mustard-colored debris from pool surfaces.

Clarifiers

These can last up to five years when stored in places that are kept cool and out of the sun, though storing them outside, in garages or sheds that reach higher temperatures reduces effectiveness and, when exposed to freezing temperatures, they can become unusable.

For the most healthful sparkling clean water possible use a super clarifier once a week for desired water clarity.

Cyanuric Acid

When maintained in containers that are hermetically sealed correctly, it is possible for this chlorine stabilizer to maintain its potency for virtually an infinite amount of time.

The sun’s UV radiation has the potential to quickly break down chlorine and any of its compounds.  To cut this loss and improve the chlorine’s active life, treat it with a stabilizer.  It is compatible with chlorine releasing it at a slow rate to last longer and reduce chemical needs.

Sodium Bicarbonate

Sodium bicarbonate and calcium carbonate (alkalinity & calcium increasers) remain viable for over five years, though shelf life can be extended by keeping it in sealed containers and away from moisture, which can cause clumping.

Sodium Bicarbonate is a granular product to increase the total alkalinity in your pool water when it drops below 80 p.p.m. 

Sodium Bisulfate & Muriatic Acid

These pH reducers tend to last longer due to more robust packaging, with shelf lives of five years, though as acids they will break down containers over time. 

Sodium Bisulphate also called pH minus is a granular form of muriatic acid and is safer, easier and less corrosive for lowering the pH of your pool and spa water.

Sodium Carbonate or Soda Ash

This (pH increaser) remains usable for over five years when kept in airtight containers, though humidity or moist conditions can cause it to clump and harden, causing it to lose effectiveness and eventually convert sodium carbonate to sodium bicarbonate.

Stain & Scale Chemicals

Also known as stain preventers, can last almost indefinitely when stored indoors in cool, dry locations and kept in tightly sealed containers, though exposure to heat or cold can affect its effectiveness.  Typically, they last 5 years. 

Doing all this, along with keeping them away from direct sunlight and water can allow some chemicals to last well over five years. Remember, however, that if the chemicals get too hot they will start to degrade. Also, if exposed directly to water they will dissolve, though humidity in the air will not affect them adversely. Generally, depending on how and where pool chemicals are stored, they should last 3-5 years.  While understanding how and where to store the above chemicals is important, it’s also important to understand where and how to store other pool chemicals.