How long will dry ice last in a swimming pool

Today's question comes to us from the Not a Very Good Idea Division of the Too Much Time on Your Hands, Co., a fully owned subsidiary of Valley 101, Inc. Here goes:

It's that time of year again when the water in our pool is too warm to refresh us. Every summer I wonder whether dumping in some dry ice would cool the water in a 10,000-gallon pool by 4 or 5 degrees and, if so, how much it would take. Is this at all feasible?

Dry ice, of course, is frozen carbon dioxide — about 107 below zero.

If you put, say, 60 pounds of dry ice in an average size pool here's what would happen:

Providing the water wasn't too cold, it would create a kind of fog, which might be kind of neat for a Halloween patio party.

It also would create a potentially toxic layer of carbon dioxide at the surface level, and will throw your pool's acidity readings way out of whack.

As for the cooling effect, not very much.

When dry ice is exposed to water it goes directly from a solid to a gas and that gas dissipates too quickly to really cool the water.

By comparison, it would take, depending on what you read, somewhere between 500 and 1,000 pounds of real ice to cool an average size pool by 5 degrees.

It would be much easier and cheaper to get some sort of aerating device — a solar-powered fountain pump or even a hose with a spray nozzle — and use it to spray pool water in the air.

Evaporation would cool it as it falls back into the pool.

Halloween is a few weeks away? Are you planning on hosting a Halloween bash?

Well, if you own a pool, you’re in luck. You have the perfect party setting even in the fall. Though the air is crisp and it’s too cold to swim, your pool can be the star of the show this Halloween.

Read on to learn why dry ice in the pool will take your spooky party to the next level. 

How Dry Ice Works

Dry ice is frozen carbon dioxide. 

To understand how dry ice works, we need to talk science. But don’t worry, you won’t have to take a test on this!

Molecules (regardless of whether they are a liquid or a solid) stay together due to the attraction of ions.

Dry ice is very cold. We’re talking -109.3 degrees Fahrenheit (-78.5 degrees C). As you may recall from grade 9 science, sublimation means that as a solid breaks down, it turns into a gas and not a liquid.

That’s what happens with frozen carbon dioxide. As it melts, you get a gas or a fog instead of a messy wet puddle the way you do with regular ice.

To create a fog effect, drop chunks of dry ice into a heated pool or a bucket of hot water. The ice will immediately begin melting, emitting white vapors that create an effect similar to a fog machine.

To keep the fog effect going, simply continue adding ice. If you are using a bucket of hot water, you’ll need to replace the water once the dry ice has cooled it down. With a heated pool, you won’t need to worry about replacing the water. 

Dry Ice Safety

As you can likely tell from the temperature we mentioned above, it is imperative that you are very careful when you handle dry ice.

You must wear thick, heavy gloves when picking up dry ice. Latex or rubber cleaning gloves just won’t do. It’s wise to also use tongs as well as heavy gloves when putting dry ice in your pool.

If you touch dry ice with your hands, the extremely cold temperature can cause real damage very quickly. So don’t do it.

You never want to put dry ice in your mouth for the same reason. 

Also, ventilation is important when dealing with dry ice. You need an area that has good airflow. Regular air is made up of 78% nitrogen, 21% oxygen and only 0.035% carbon dioxide.

If the level of carbon dioxide rises higher than 5%, it can be toxic.

That’s what makes your outdoor pool a perfect spot for your dry ice decor. There’s excellent ventilation. If you are hosting a Halloween party in your backyard, use your pool as a decor feature, but don’t plan to go swimming. For one thing, it’s too cold in October. And for another, the high levels of CO2 are too much to breathe in.

That means you should never use dry ice in an indoor pool. 

Just make sure you and your guests don’t stick their head in the fog. This fog is a zone of high CO2 concentration. As we said, too much carbon dioxide is dangerous to your health.

Why You Should Put Dry Ice in the Pool

Now that we’ve talked about the dangers of dry ice, let’s move on to why it’s a great idea to put dry ice in your pool this Halloween.

Let’s face it, your pool takes up quite a bit of your yard space. And if you are hosting a Halloween party, it’s probably a costume party and not a pool party. 

But maybe you haven’t gotten around to closing your pool for the winter. Well, no worries, dry ice can make your pool your main decorative attraction.

Dry ice will make amazing bubbles and fog. Your guests will feel like they are lost in the moors of Wuthering Heights or in a haunted graveyard.

You can also use red, purple, or green spotlights to make your fog look creepy and awesome. 

Another reason dry ice is the way to do is that dry ice is inexpensive compared to most other decorations. You can get big chunks of frozen carbon dioxide for a few bucks.

A little dry ice goes a long way. Throw a small chunk into the pool at regular intervals to keep the spooky fog going all night long.

Enhance Dry Ice in Swimming Pool with Decor

Your dry ice pool is sure to be the talk of the party. But you can take your spooky get together to the next level with some well placed decorative items for the ultimate wow factor.

Why not add a few skeletons in your pool. They will look as if burned alive in acid with the fog rolling over them. Pose your skeletons with jaws gaping and arms outstretched as if they are climbing out. 

You can also use some buckets of hot water and dry ice along the edge of your fences. That way, your guests will feel completely isolated from the world. What neighbors, they’ll say.

Don’t forget to play a spooky soundtrack (Thriller, anyone?) for a party your guests will never forget.

Final Word on Dry Ice in Pools

 We hope this article about how to safely use dry ice in the pool helps you up your Halloween party this year.

Remember, Sahara Construction and Custom Pools is your best bet for all your pool and outdoor living needs. Ask for a free consultation today.

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