Do Pool Testing Chemicals Ever Expire?

Pool testing chemicals are some of the most important parts of your swimming pool supply kit. They let you know how much of each chemical needs to be added and when it’s time to make adjustments. Much like all pool chemicals, there are numerous issues that can dilute or ruin your testing chemicals, but can they expire?

Pool testing chemicals expire at the labeled expiration date on the bottle. If there’s no expiration date, discard the testing chemicals 180 days after opening them. You should test your pool water weekly, so it’s unlikely that your testing chemicals will expire before they’re empty.

In this article, you’ll learn whether or not pool test drops and strips go bad, how you can know when they’re expired, and how to make them last longer.

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Do Pool Testing Reagents Go Bad?

Pool testing reagents can go bad, but they last a lot longer than pool test strips. While most test strips only last a few months, you can often get twice as much longevity from the testing drops. Pool Contractors Supply claims some people get up to two years out of their pool test reagents, but that’s not a guarantee.

Unfortunately, there are quite a few factors that can shorten your testing chemical’s lifespan. Below, we’ll take an in-depth look at the most common causes.

  • Low-quality test strips don’t last too long.
  • Liquid testers last longer than test strips.
  • Leaving the test chemicals and strips in bad conditions (humidity, heat, freezing temperatures, etc.) will shorten their longevity.
  • Always look at the expiration date before picking up a new bottle of test strips to ensure you get the newest kit.
  • Make sure nothing gets in the bottle; it can change everything about the way the chemicals test your pool water.

The Poolmaster Essential Collection Chemistry Set is a top-notch kit with all of the reagents you need to test your pool water. It checks chlorine, bromine, pH adjustments, alkalinity, and a couple of other chemicals. It’s made with high-quality airtight seals to preserve the chemicals for as long as possible. This kit also has a guide that lets you know how much of each chemical to add.

Do Expired Pool Test Strips Work?

Expired pool test strips won’t work because they reveal incorrect results. Their accuracy is tarnished once they’re beyond the expiration date. Furthermore, they’re much more likely to break apart or crack when they’re dipped into the water. Some test strips last longer than others, so make sure you check the expiration date and don’t use them beyond it.

The best way to know if your pool test strips are expired is to test them against another set of strips or reagents. You could also bring a water sample to a local swimming pool store if they do free tests (which many of them offer). If the strips have different readings than the potentially expired strips, they need to be replaced.

In most cases, expired or bad test strips show little to no difference in color. When you dip them in the water, they don’t change at all. Unfortunately, these incorrect results lead pool owners to add too much chlorine, muriatic acid, cyanuric acid, soda ash, and many other chemicals. Their pool turns into a dangerous chemical soup.

AquaChek reveals one of the most reliable tips, which is to never put wet fingers or hands near the test strips. Too much moisture can ruin the test strips and dilute the reagent drops, so it’s important to dry your hands beforehand. Let’s dive into a handful of ways you can make them last longer in the following section.

How Long Are Pool Testing Chemicals Good for After Opening?

Pool testing chemicals are good for about half of a year after opening. This means you shouldn’t have any trouble making one set of test strips or reagents last through a full swimming season. Keep your test strips away from humidity and make sure you don’t get any pool water in the bottle.

Try these tips to make your pool testing chemicals last as long as possible:

  • Store them in a room-temperature location away from extreme temperatures. Most pool testing chemicals can’t be exposed to extreme heat or freezing weather. Once they get too hot or cold, they won’t work anymore. You’ll test the water and everything will read zero or low, which isn’t always accurate.
  • Don’t expose any pool testing chemicals to excessive amounts of humidity. Seal the bottles and keep them in an airtight storage container if possible. Too much moisture from the pool, rainwater, or ambient humidity can ruin the test strips. These strips activate the second they touch the water.
  • Keep your testing chemicals and strips upright. When they’re on their side or upside down, the strips have a higher chance of getting damaged. This tiny detail can make a world of difference in how long your testing chemicals last. You can store them next to other pool chemicals, but never leave them exposed to the open air.
  • Never put used test strips or drops back in the bottle. Some people reuse the test strips, but they don’t work once they’re used. You might have a few shade changes, but you’ll end up wasting your time. It’s much better to use fresh test strips or testing reagents than to reuse old ones.

One Drop recommends throwing away your pool testing chemicals 180 days after opening them. Even if they have an expiration date, there’s a good chance they’ll be ineffective in this timespan. Using expired or bad pool test strips and drops will yield incorrect results, causing you to make unnecessary adjustments to the pool’s chemistry.

Testing chemicals are an important tool for a pool inspection. They make the inspector’s job easier and faster. Before you leave, I recommend reading my guide on how long pool inspections take to get an idea of the process and its steps. [How Long Does a Pool Inspection Typically Take?]

pool cleaning and maintenance products

Final Thoughts

Although pool test strips and drops expire, you can get the most out of them by using them within the recommended date range. Remember to store your testing chemicals in a room-temperature, dry place without too much sunlight. Always seal the pool testing chemicals after using them to prevent them from going bad.