Is It Ok To Put Dry Ice In A Swimming Pool?


For those with swimming pools, there is typically a point where the summer sun has heated up the water, and instead of being refreshing, it is reminiscent of a lukewarm bath. People in this situation may be looking for ways to bring some much-needed coolness back to the water. Dry ice is very cold (-109 degrees Fahrenheit compared to the 32 degrees Fahrenheit of regular ice), which may lead pool owners to wonder if it is okay to put dry ice in their swimming pool. 

It is okay to put dry ice in an outdoor pool. However, dry ice dissipates into gas once it hits the water, so it will only cool a pool a small amount, if at all. Additionally, handling the amount of dry ice you would need to be effective in a pool can be very dangerous and is probably not worth the risk. 

However, you may be having a Halloween party or just really like the ghostly effect that dry ice can bring and are going for a specific vibe or look for a special occasion. If this is the case, take a look at the following precautions to take, how to handle dry ice, and why putting dry ice in an indoor swimming pool is never recommended.

Is it Okay to Put Dry Ice in an Indoor Swimming Pool? 

It is never okay to put dry ice in an indoor swimming pool, although you can certainly do so with outdoor swimming pools as long as you take the right precautions. 

So, if it is permissible to put dry ice in an outdoor pool, why is it different for an indoor pool? 

When dry ice hits the water, because the water is so much warmer, the interaction between the two produces enough energy so that instead of causing the dry ice to simply melt into the pool as regular ice would, it instead escapes as a gas that hovers over the surface of the pool. This gas is CO2, which causes asphyxiation (or lack of oxygen to the brain), so it is unsafe to swim in the pool (indoor or outdoor) when this gas is present. 

With an outdoor pool, this gas will eventually dissipate and drift away, so the pool will eventually be safe to swim in once more. However, with an indoor pool, the CO2 has nowhere to go and can quickly become dangerous to anyone inside or near the pool. 

Considerations Before Adding Dry Ice to the Pool 

If you have an outdoor pool, there are still some risks and safety factors that are important to consider before you put dry ice in it: 

Dry Ice is Extremely Cold

As stated previously, dry ice is extremely cold at -109 degrees Fahrenheit minimum. Whereas you can hold a regular piece of ice in your hand, if you try to do that with dry ice or even if your skin brushes against it slightly, then you run the risk of frostbite within seconds. 

With that said, if you are planning to transfer dry ice from a container into your pool, make sure to do the following:

  • Wear insulated gloves. If at all possible, use tongs for transferring the ice from one place to the other. However, if you don’t have tongs, be sure to use insulated gloves or an oven mitt for proper protection. Even if you are using tongs, wear gloves anyway for another layer of protection. 
  • Wear long sleeves, pants, and close-toed shoes. This is especially important if the ice is in a block that you will have to chisel into. That way, you will not have to worry about bits of ice flying through the air and landing on your bare skin. 
  • Wear protective goggles. Anytime you are cutting or chiseling away at something, you should wear goggles. However, it is especially important for cutting into dried ice, as if a shard lands in your eyes, it could cause irreparable damage. 

Dry Ice Converts into CO2 Gas When Exposed to Water

As mentioned before, when dry ice is put into water, it turns into a gas that hangs in the air, leading to reduced levels of oxygen and the potential for asphyxiation if you are not careful. For taller adults, this is not much of a concern as their heads will usually be above the point where the gas rises. You will be fine as long as you don’t get into the pool while the CO2 is hanging in the air. 

However, for kids and pets, it is an entirely different story. This is for two reasons:

  1. The CO2 will eventually sink to the lowest point of the room. For children and pets who are lower to the ground, this means they will take in the full effect of the CO2. 
  2. Because a child’s metabolism is higher than adult humans, the CO2 will work more quickly and is thus far more dangerous for them.

With that said, it is important to follow these precautions when planning to add dry ice to your pool:  

  1. Leave the kids inside or at home if you know there will be dry ice added to the pool (or make sure you add it after they are in bed).
  2. Keep your pets indoors while the CO2 is in the air.

Dry Ice Can Be Explosive

While you do not have to worry about anything catching on fire with dry ice, because it does produce a lot of energy as it turns into gas—depending on what kind of container you put it in and where you put that container—it has the potential to explode, causing hearing issues or leading to shards of the container or ice to hit you. 

With this in mind, you’ll want to take the following precautions: 

  • Store it in a proper container. The best container to store dry ice is an insulated container with enough room for the inevitable expansion due to the ice dissipating into gas. Whatever you do, make sure you do not seal the container shut as this can cause pressure to build. At that point, the gas will have nowhere to go, leading to the container exploding. 
  • Keep the container of dry ice in a well-ventilated area. You may think it is best to store the dry ice in as cold of an area of the home as possible, such as in a basement or a walk-in freezer. However, this is wrong for a few reasons. One, the dry ice will automatically start turning into a gas at any temperature above -109F. Two, if you put it in an enclosed space like a walk-in freezer, the gas will linger and could be dangerous.

Dry Ice Requires Careful Disposal

Now that you know the proper ways to handle, store, and when to use dry ice, how exactly do you get rid of any excess that you may not have used in your pool?  

The following includes some proper and effective ways to dispose of any extra dry ice and what to avoid doing when trying to dispose of it.

Dry ice disposal do’s:

  • Leave it outside or in a well-ventilated room with the windows open and let it melt. This is the simplest and least troublesome way to get rid of it but may take a while depending on the temperature of the area it is in.
  • Pour warm water over it until it is melted. Maybe you’re in a bit of a time crunch or need to clean up quickly. If that’s the case, pouring warm water over the dry ice is an effective way to quickly dispose of it.

Dry ice disposal don’ts: 

  • Do not pour the dry ice down the toilet or in your sinks. The sublimation can put pressure on your pipes and cause them to burst, leaving you with more of a mess. 
  • Do not put your dry ice in the trash. It can release carbon dioxide into the air, and since most trash cans and trash bags are not well ventilated, it can be dangerous both to you and to waste collectors. 
  • Do not leave the dry ice in an area where children may be. Kids are curious about new things, but even if the dry ice is dissipating, it can still be dangerous, both in terms of asphyxiation and potential frostbite if touched. 
  • Do not leave it to melt in a room without proper ventilation (windows). Doing so will lead to a concentrated amount of CO2 left in the air, but instead of dissipating into the air, it will hang in the air.  

Dry Ice Can Affect Future Pool Maintenance

Not only can dry ice pose a danger to your family and guests if mishandled, but adding it to your pool can make it extremely difficult to maintain proper alkaline levels for safe and sanitary swimming.

When CO2 (dry ice) is added to pool water, it can drive the alkaline levels in the pool water down. This can cause the pH levels to rise and fall rapidly; this constant back and forth is not great for your pool. 

Low pH levels make the water acidic; the acid in the water can cause the following:

  • Itchy and irritated skin and eyes. The acid in the water dries your skin out, which in turn leads to itchiness and soreness. 
  • Cracking and pitching on the pool’s surface. Acid wears down on the surface over time, causing holes and wear that would otherwise take much longer to occur.
  • Metal corrosion. This is bad news for the pipes, filters, and screws in your pool and can lead to discoloration of the pool walls and water contamination. 
  • Pool sanitizers don’t work as well. This will lead to you adding more sanitizer to the pool for the same results, which can get expensive fast. 

On the flip side, when the pH levels are too high, other problems can occur, such as the following:

  • Water scaling. Water scaling is a buildup of minerals on the surface and appliances of your pools that can cause damage. Water scaling is also known as water hardness.
  • Poor water circulation. This happens due to the overall buildup of minerals in the water. The mineral buildup clogs the filters, meaning you will need to clean them out more, and they are overall less effective at cleaning and circulating the water.
  • Higher water pressure. Because there is more buildup in the filters and the pipes, more force is needed to get the water through. This can lead to the pipes and filters cracking as well as your water pump needing to be replaced sooner than it would have otherwise. 

Alternatives for Cooling Down a Swimming Pool

The short of it is that while adding dry ice to your pool (if it is outdoors) can be done if the proper precautions are taken, overall, it is not an effective way to cool off your pool. So, what are some things you can do instead if you find your pool water in the lukewarm range?

Shade Your Pool

The simplest answer is to either put up a shade or, if you are planning on building a pool, build it near trees that can offer some natural shade. If there are no trees nearby, some affordable shading options include: 

Use a Pool Mister

Another way to lower or maintain a cooler pool temperature is by adding a mister; the evaporation helps cool the water. Some mister options include the following:

Final Thoughts

If you have an outdoor pool and want a cool ghostly effect for a party, you can add dry ice. However, it is important to take the proper precautions, such as wearing long sleeves, gloves, and eyewear and only using it when there are no children or pets around. Additionally, you should not go swimming in it right away as the CO2 levels will be high and can cause asphyxiation. 

But, overall, adding dry ice to your pool, whether indoor or outdoor, comes with many issues and is a highly inefficient way of cooling your pool. Instead, choose a more affordable and safe option such as a shade or a water mister.

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