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Can pool chemicals expire?

pool chemicals

Almost everything has a shelf life, so of course, your pool chemicals would have an expiration date. However, most pool owners will use up the chemicals they purchase before they expire. That being said, it’s still important to know which you can continue using safely, and which you should chuck into the garbage bin.

Types of pool chemicals and their expiration

Chlorine

There are three different types of chlorine, and all have different shelf life.

  • Liquid

Liquid chlorine has the shortest shelf life of all pool chemicals since it begins to lose 50% of its effectiveness after just six months. Lengthen that time up to a year, and you lost 90% of its potency. Keep in mind that this loss of potency is made worse if stored incorrectly. This is one pool chemical that won’t survive Canadian winters — you’d be much better off buying a new one once you decide to open your pool again.

  • Tablet

Chlorine tablets, also known as Trichlor tablets, have the longest shelf life of all chlorine products. In fact, if stored correctly, you can potentially keep these tablets for 3-5 years (sometimes even longer)! After 3 years of being properly stored, they will still hold 98% of their chlorine content. We can see why this is the most popular type of chlorine among pool owners.

  • Granular or shock

Granular chlorine also has a pretty long shelf life. If properly stored, this type of chlorine can also last you over 5 years! However, if it comes in bags, the bags usually can start to dissolve after 12 months, so you might want to consider purchasing the bucket version or packing the granules into Ziplock bags.

Cyanuric acid

Stabilizer, or cyanuric acid is one of those magic chemicals that can last indefinitely. It can even absorb moisture and still work fine as long as it’s in a container that is properly sealed. This makes sense considering how often you should be using it. In fact, unless it’s extremely hot outside and you don’t maintain your pool’s chemicals properly or regularly, you shouldn’t have to use stabilizers very often. Some people even use theirs only once per year!

Algaecides

Algaecides have a surprisingly long shelf life given how often we use them. It’s one of those chemicals that tends to run out before they expire since they’re usually used on a weekly basis. If properly stored, algaecides can last up to 5 years, but you have to ensure that you put them in an area that is neither hot nor cold, as they will lose their effectiveness.

Clarifiers

Pool clarifiers, like algaecides, can last up to 5 years when kept firmly covered in a dark and cool place. Clarifiers can lose their potency when kept outside or in a hot environment and, just like algaecides, temperatures that are too cold can ruin the polyamide structure and make them ineffective.

Alkalinity & Calcium Increaser

Dry white powder or flake chemicals such as Sodium Bicarbonate and Calcium Carbonate can maintain viability and potency for over five years. As with other pool water balance chemicals, shelf life may be increased by keeping the chemicals in tightly closed lids to inhibit moisture, which may cause clumping and hardening.

What about pool maintenance accessories?

It’s important to store swimming pool chemicals correctly to ensure that they last for years, but some pool-maintenance supplies expire more quickly. You will need to replace test strips and reagents after one to two years because they will expire. If you use old test reagents or strips to test the water, you will receive inaccurate results, so you should replace them before they expire. For example, you may want to discard any unused supplies after winterizing your pool and replace them with new equipment when you reopen it.

How to store your pool chemicals

In a cool dry place

When keeping pool chemicals, the first thing you should do is keep them out of direct sunlight and/or humid environments. Many pool owners are unaware that sunshine and humidity can cause pool chemicals to react poorly, which might result in potentially dangerous fumes. These substances can react dangerously with even a tiny amount of water. The optimum location for storing pool chemicals is somewhere dry, out of direct sunlight, and sufficiently distanced from your pool. Additionally, you have to try to preserve them in distinct containers with properly closed lids.

Ventilation

If you keep all of your pool chemicals in one location, it’s crucial the space is well-ventilated. Ventilation won’t stop the fumes from developing if the chemicals are mixed by mistake, but it will stop them from building up and growing worse.

No flammable materials

It’s crucial to think about whether or not combustible materials are being stored with your pool chemicals. While following the instructions on the packaging will assist to reduce the likelihood of hazardous situations occurring, storing them away from combustible objects will provide you peace of mind in the event that a spilling mishap should occur.

Don’t reuse containers

When purchasing pool chemicals, some individuals might choose to utilize their own storage containers, but this is never advised. To minimize the dangers involved with reusing or simply swapping containers, it is always preferable to preserve chemicals in their original containers. Additionally, it’s a good idea to wash out the containers after using them before throwing them away. Switching containers poses a serious danger since you can unintentionally mix the contents of the old container with the new one.  Moreover, you should never neglect to put on safety gear when working with these substances, such as goggles, long sleeve shirts, gloves, and shoes.

If you’re not sure about whether or not you’re properly storing your pool chemicals or whether they’re expired, contact a pool professional. You can even lift the burden off your shoulders entirely by contacting a professional for weekly pool maintenance.

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