What Chemicals Are Needed to Open an Above Ground Pool?

above ground pool deckSome choose to drain your above ground pool for the winter, while others simply cover it. No matter which method you prefer, it’s important to know what chemicals you need when it comes time to open it back up for the spring.

When comparing inground and above ground pools, or pools that have or haven’t been drained for the winter, there is a lot of overlap between products and processes. However, the small difference can make or break the task of establishing a swim-ready pool.

Because people who own an above ground pool are more likely to do their own pool maintenance, it’s good to have a working understand of the various chemicals that keep your pool water healthy and stable.

If you would rather have the professionals take care of your spring pool preparations for you, Sun Valley Pool Service is happy to send out our experienced pros to assist with Pool Cleaning Service.


Before adding any chemicals, it’s imporant to do a bit of basic cleaning. If your pool has been uncovered for any length of time throughout the colder months, you will need to use your skimmer, your net, or a pool vacuum to clear away larger debris.

You will also need to be sure you have reconnected all of your pumps and hoses. Prime the pumps and put in a clean filter before turning the pumps on.


We all know that chlorine is the most important pool chemical. However, the amount needed varies greatly from one circumstance to the next. Important factors:
CYA pool tablets chemicals

  • Total water volume: The average optimal ratio for water and chlorine is about 1ppm (part mer million).
  • Average daily temperature: Long, hot days will influence your water volume due to evaporation, meaning the height of summer may require frequent adjustments.
  • Length of exposure to direct sunlight: Direct sunlight contributes to chlorine breaking down on a molecular level.
  • Frequency of use: Organic material, such as sweat and oil from our skin, makes the chlorine in your pool work “harder.” This is also true for lotions, sunscreen, etc.
  • Environmental components: Frequent rain and/or washout from your lawn can also cause chlorine to break down more quickly.

Most above ground pool owners use chlorine tablets, which have a high pH. Liquid chlorine, however, has a low pH and will eventually lower that of your pool water. This is one of the main reasons why it’s good to know how to use other available pool chemicals.


Most of us are familiar with the term “shock the pool,” with a general understanding that this means potent chemicals will be added to the water for a stringent cleansing. This process is also known as oxidizing the water.

Shock treatments mostly include chlorine, but there are blends available that also contain an algaecide. Ironically, when your pool water begins smelling bleachy, this is actually a sign that it needs a shock.

When chlorine is broken down by interacting with various contaminants, the product of that action is called chloramine. Chloramine has a bleachy smell that gives some people the impression that the water has too much chlorine. -Nope! That odor indicates that it’s time to shock your pool water.

Water Balancers

As discussed earlier, the chlorine in your pool can make the pH higher or lower. While above ground pools are more likely to have a high pH due to the regular use of chlorine tablets, there is still a risk of low pH in the use of liquid chlorine and liquid shock treatments.

This is why water balancers are available. There are 5 different types available, all of which are made from basic, naturally occurring salts and minerals:

  1. pH Increasers
  2. pH Decreasers
  3. Alkalinity Increasers
  4. Alkalinity Decreasers
  5. Calcium Hardness Increasers

If you’re starting out with an empty pool that you plan to fill with water and an appropriate level of chlorine, you may not need to add a balancer for several weeks. In fact, most of these water balancers are not products you will need to use regularly. But in the interest of checking your overall pool water chemical ratios, they are definitely good to have on-hand.


Algaecides work hand-in-hand with chlorine to keep your pool water balanced. Too much or too little of either one will offset the recommended pH, so it is wise to have both on hand.

Organic matter, both from swimmers and from leaves, etc., can give rise to bacteria if your pool’s pH has produced an ideal condition for bacterial growth. What happens next? Algae has an opportunity to set in and munch on the bacteria in the water.

Algaecides kill off the algae that is already established in your water. They’re generally available in a powder form, and are sometimes found in an overall shock treatment.

If you left your above ground pool full of water over the winter, it is practically guaranteed that you will need to use an algaecide in addition to a chlorine-heavy shock treatment. Once all the larger organic debris has been swept, lifted, or vacuumed away, these products can work in concert to restore your pool’s pH balance without the hassle of draining and adding fresh water.

For those who are starting out with an empty pool. adding the correct ratio of chlorine and balancers will do the trick. Algaecides are only necessary once you begin to suspect a problem.

If you are looking for more in-depth information about the proper use of pool chemicals, check out our Pool Chemical Guide.

test pool chemicalsCyanuric Acid

Although it is only one of many agents classed as supportive pool chemicals, cyanuric acid is perhaps the one you may encounter most frequently. In a standard pool water testing kit, this is one of only a handful of elements tested for.

Cyanuric acid works as a protective factor for your chlorine. It helps reduce the process of breakdown in chlorine that is caused by sunlight, organic matter, and other common factors.

Like algaecides, products that provide cyanuric acid may not be necessary right when you re-open your above ground pool. However, if you’re still facing issues after a good shock treatment and proper chlorine amendments, it may be time to adjust your cyanuric acid.


There are several supportive chemicals for balancing your pool water, just like there are many other purifiers, metal removers, and even a whole host of chlorine-based compounds. But when it comes down to knowing the basics, this article offers a helpful overview.

For those who are preparing to re-open their above ground pool for regular use, these chemicals are the most important ones to have on-hand.

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