Can Chlorine Tablets Damage Pool Liner?

So you want to shock your pool without shocking your wallet? Chlorine tablets can be useful in decontaminating your pool and making it safer to swim. But if you aren’t careful, the tablets can do more harm than good.

Chlorine tablets can damage pool liner if they come in contact with the liner’s vinyl material, which gets rapidly bleached and weakened when exposed to concentrated Chlorine. It is wiser to use the tablets with a chlorine dispenser or use granular Chlorine alongside chemical stabilizers.

In this article, you will not only learn how to avoid pool liner damage caused by chlorine tablets but will also discover what other factors can affect the vinyl liner. Among the factors discussed in this post are sunlight, temperature changes, and extreme heat. By the end, you’ll know how to keep your pool liner protected.

Why Do Chlorine Tablets Eat Away the Liner?

Chlorine in small doses doesn’t ruin the pool liner, and if it did, the industry would find a replacement to shock pools. Fact is, most pool-tier chlorine doses are safe for a swimming pool because water circulation keeps Chlorine from coming in constant contact with the same patch of the pool liner. Just like with sunlight, persistence is required to cause damage.

Chlorine tablets are heavy and concentrated. When they sit on any surface, they expose it to high chlorine dosage. Such dosage can be harmful to a range of materials, including the vinyl that makes up the pool liner. Since chlorine tablets cause the most damage to pool liners, they’re seen to be the exclusive threat to swimming pools. 

That is far from the truth as a range of factors can affect the pool liner in similar ways. You’re wise to have looked up Chlorine tablets’ potential impact on the liner, but it is imperative that you understand the remaining factors as well.

What Else Can Damage a Pool Liner?

Prolonged Sunlight Exposure

Not only does sunlight speed up Chlorine reactivity, but it also contains UV rays that have an adverse impact on vinyl. From bleaching to sudden cracking, the vinyl liner doesn’t take very well to prolonged periods of receiving sunlight. 

Thankfully, there are a few ways you can prevent persistent sunlight bombardment, and the following post goes into detail on how the sun affects the liner and what you can do to prevent damage.

Sitting Water

As covered above, persistence is critical to liner erosion. When water has a high enough concentration of Chlorine, and the pool circulation is switched off for an extended period, Chlorine in the pool water’s other most layers gets to sit atop the liner. This starts to weaken the liner. 

Even if your pool circulation isn’t off for a month on end, having chlorinated water sit still for a few hours every day can sufficiently erode the pool liner. One of the ways to prevent this is to use chlorine stabilizers alongside Chlorine. This way, the chlorine threat will not prevent you from switching off the pool circulation and saving electricity in the process.

Sudden Temperature Changes

In the absence of concentrated chlorine threat, you have a different threat to worry about: temperature. As good as vinyl is for swimming pools, the material doesn’t seem to be a fan of temperature changes. 

Whether your pool temperature changes from cold to hot or vice versa, it must not be drastic as sudden changes will expand or contract the vinyl liner too much and cause material degradation. Fortunately, most heating and cooling processes are gradual. Just make sure you don’t heat a super-chilled pool by turning the heat pump all the way up.


Even when your pool is lukewarm, overheating it is not a good idea. Heat can cause cracking in vinyl, and while this may be easier with vinyl flooring than with vinyl liner, it still is a factor to be cautious of nonetheless. Heat the pool only to the point that is needed, and don’t overindulge yourself. And if you do, just know that you are sacrificing your pool liner’s health.


This is a fancier way of saying: make sure your pool is appropriately drained before the closing season. If there’s water in the pool and it freezes, guess what happens to the vinyl liner? It simultaneously contracts because of the temperature and has to stretch because of the water/ice volume. 

The result is the complete destruction of the pool liner, which warrants immediate replacement in the subsequent swimming season. But since most pools are closed properly during the winter, this isn’t as big of a vinyl deterioration factor as sunlight exposure.

How to Prevent Chlorine Damage in Pool Liners?

You can avoid chlorine damage by not using Chlorine, but that’s not a feasible option as water requires chlorination to remain contaminant-free. The option of using a saltwater chlorinator comes to mind as such a device creates a diluted stream of Chlorine that doesn’t impact a vinyl liner. However, such chlorinators do not generate nearly enough Chlorine to shock a large pool. They’re more suited for hot tubs.

If using Chlorine is a must and you need to use it in a sufficient quantity, then the best way to go about it is to use chlorine-stabilizing chemicals. These are available at most stores that sell pool equipment. You can also get a chlorine dispensing device that acts as a barrier between the liner and the chlorine tablets. Aquatica Pool Chlorine Floater Dispenser is an example of such a product. This floater sits well above the liner as it is on the pool’s surface. 

Holding three chlorine tablets and consisting of 15 vents, this product provides you with optimum control over how much Chlorine gets dispersed in the water. With over 4,000 reviews that come to a collective average of 4.7 out of 5 stars, one can assume it is effective at its job and doesn’t ruin pools like popping tablets into a skimmer does.

Final Thoughts

Chlorine tablets are concentrated and contain a heavy dose of Chlorine that is far beyond what vinyl can handle. If they come in direct contact with your pool liner, they will bleach it or even eat through it entirely. The best way to avoid this is to use granular Chlorine alongside the appropriate stabilizers but if you insist on tablets, then use a chlorine dispenser that prevents the tablets from touching the vinyl liner.

Jed Arnold

Jed spent every year from the ages of 15 - 22 as a Lifeguard (Red Cross) and ages of 17 - 22 as a Certified Pool Operator (CPO). Between working for over a dozen facilities and owning a pool, he carries over a decade of pool experience.

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