How to Treat the Water in an Inflatable Pool

Inflatable pools used to be limited to the kind of "kiddie pools" you could easily blow up with a small hand pump. These pools held about 30 gallons of water, and it was a simple matter to empty them out every day and just fill them up again with fresh water each time you wanted to take a dip. Modern inflatable pools can hold hundreds or even thousands of gallons, so treating the water with chemicals is less wasteful than dumping the water and replacing it. Large inflatable pools need a circulation/filtration pump to disperse chemicals and remove contaminants from the water.

Enjoying the still water on a summer day.
credit: Photo by frank mckenna on Unsplash
Small pools need sanitizing just as much as large ones.

A Potential Health Hazard

The Centers for Disease Control does not recommend the use of small inflatable pools in situations where large numbers of children are present. Such situations include camps, small daycare facilities and even multifamily recreational facilities. The CDC recommends inflatable pools only for single-family use, based on the assumption that children in the same family already bathe together.

The CDC recommends replacing the water in an inflatable pool after each use. When this is impractical, the pool should have a portable filtration water circulation and filtration system. Some pools come with their own filtration system. If you need a standalone filtration system, you can buy one for about $30.

Assuming you have a filtration system for your inflatable pool, you still need to use chemicals to treat the water to maintain acceptable pH and alkalinity. You also need to maintain acceptable free chlorine and cyanuric acid (CYA) concentrations to sanitize the water and kill pathogens.

A Procedure for Treating the Water

It's just as important to maintain the proper chemical balance in an inflatable pool as it is in a regular one--perhaps even more so, because the smaller volume of water heats up quickly in the sun. After you test the water, adjusting the pH is the next step, because the water acidity affects the ability of the chlorine you add to sanitize.

Step 1

Purchase commercially manufactured test strips to check your pool's pH, as well as its chlorine and CYA levels. CYA is a stabilizer that protects chlorine from sunlight. Without it, the chlorine quickly breaks down and becomes ineffective. The ideal levels are as follows:

  • pH: between 7.2 and 7.6
  • Free chlorine: between 1 and 3 parts per million
  • CYA: between 25 and 50 ppm.

Step 2

Calculate the volume of water in the pool to determine how much of each chemical you need to add. To do this, measure the pool's radius (r)--the distance from the center to the edge--and calculate the surface area using the equation: Area = πr2. Multiply this by the depth of the water. If all your measurements are in feet, the result will be in cubic feet. Convert this to gallons using the factor 1 cubic foot = 7.5 gallons.

Step 3

Adjust the pH before adding chlorine. Chlorine doesn't work well in alkaline water, and acidic water destroys the pool liner. Lower the pH by adding muriatic acid or sodium disulphate, and raise it with baking soda or soda ash. Consult the containers for the amount of each product to add, based on the pool volume and the amount you need to adjust the pH. Circulate the water continuously for an hour or more after adding each chemical.

Step 4

Shock your pool with a large dose of chlorine, and wait for the chlorine level to fall below 3 ppm before allowing anyone to use the pool. You can purchase special pool shock treatments in the form of chlorine granules, which are to be mixed with water and then poured into your inflatable pool. It is important to make sure that no undissolved chlorine granules settle to the bottom of the pool, as these may harm the liner.

You can also shock your pool with liquid bleach. Measure out 2 1/2 tsp. of bleach for every 100 gallons of water your pool holds (or 1/4 tsp. for every 10 gallons, if you have a smaller inflatable pool). Add the bleach to a bucket of water, and pour the water into your pool. Circulate or stir the water to make sure all of it gets chlorinated.

Step 5

Keep debris out of your pool by covering it when it is not in use. Covers are available for inflatable pools ranging from 8 to 24 feet in diameter.

Step 6

Drain your pool daily or weekly if it is small enough to do so. If you have a large pool, try to drain it at least once a month, as no amount of chemicals can clean the water of all of the dead skin cells, bugs, leaves, or just plan dirt that will accumulate there. When your pool is drained, scrub it out with mild detergent and a soft scrub brush to clean any scum or buildup off the pool walls.