How to Treat Your Pool Water for the First Time

Written by Michael Dean
December 19, 2023

swimming pool chemicals

So, all the paperwork and construction work is done, and you’re the owner of a brand new swimming pool! Now it’s time to treat your pool water so it’s safe for you to swim in and enjoy the fruit of your labors and investment.

In this article, I will go over my step-by-step process for treating your pool water for the first time – for both traditional chlorine pools and saltwater pools.


Main Takeaways

  • Pool chemicals you’ll need to shop for to treat your pool water for the first time include pH and alkalinity adjusters, calcium hardness increase, chlorine, cyanuric acid, and pool shock.
  • To start up your pool, you’ll need to run your filter, adjust TA, pH, and calcium hardness, and add chlorine and CYA.
  • To start up a saltwater pool, you’ll also need to add salt and activate the SWG.
  • You should treat your pool water often. Some chemicals need to be checked and adjusted every week, while others can go an entire month without any need for a top-up.

What Pool Start-Up Chemicals Do You Need?

The initial chemicals you will need to add to your pool for the first time are vastly important. It’s essential to keep these chemicals on hand, as you’ll need them as you continue to look after and maintain your pool. Here’s a quick rundown of what you’ll need, why they’re important, and their recommended ranges.

pH and Alkalinity Adjusters

To help adjust your pH and alkalinity, you’ll need baking soda (to raise pH and alkalinity) and sodium bisulfate or muriatic acid (to lower pH and alkalinity).

Both pH and alkalinity are super important to the health of your pool water. The ideal pH range is typically between 7.2 and 7.8, while the recommended range for total alkalinity is between 80 and 120 parts per million (ppm).

Calcium Hardness Increaser

Calcium hardness is also crucial for the health of your pool water, as it helps stabilize pool pH and prevents corrosion. The ideal range for calcium hardness in a pool is around 200 to 275 ppm for a concrete pool and 175 to 225 ppm for a fiberglass or vinyl pool.

Chlorine (or Alternative Sanitizer, Such as Bromine)

Of course, when you treat your pool water for the first time, another chemical that is an absolute must is your choice of sanitizer. This kills any bacteria, algae, and other nasty contaminants present in the water and sanitizes the water for human use. Chlorine should always be between 1 – 3 ppm.

Pool Stabilizer (Cyanuric Acid)

A pool stabilizer, such as cyanuric acid, protects the chlorine in your pool, preventing it from breaking down rapidly due to UV rays in sunlight. It should typically be between 30 – 50 ppm.

Pool Shock

This is chlorine on steroids. When you start up your pool, if the water is especially dirty, you may need a very high concentration of chlorine to boost the sanitization level of your pool.

I know… All of this might seem like an intimidating list of products, but don’t worry! I’m here to help you understand how to use them. The next section will cover how to add these chemicals and in what order.

Pool Start-Up Chemicals Procedure: Step-by-Step Process

Here’s my easy-to-follow step-by-step process to start up your chlorine pool. Of course, before you jump in, make sure you fill the pool first! The pool water should be at the halfway point of the skimmer opening.

Step One: Run Your Filtration System

Once the pool is full, you’ll need to run the filtration system so that all the chemicals you add to start up the pool can fully circulate and treat the water so that you can use the pool as soon as possible!

Step Two: Adjust pH and Alkalinity

Test your water for pH and alkalinity. As mentioned, alkalinity must be around 80 to 120 ppm, while pH should hover between 7.2 and 7.6. Depending on the ranges, use your choice of pH increaser or decreaser.

Pro-tip: ALWAYS pre-dilute your chemicals before adding them to the pool water—especially if it’s an acid!

Step Three: Add Calcium

Once you have adjusted the alkalinity and pH levels, you’ll have to test and adjust calcium hardness levels to the correct range as well.

Step Four: Add Chlorine

After 72 hours, and once your TA, pH, and calcium have completely adjusted, add your chlorine. If needed, pre-dilute the appropriate amount in a bucket and pour it slowly into the pool while walking around the perimeter. Keep your filter running to ensure even distribution.

Step Five: Add Cyanuric Acid

Once you’ve tested the water and everything is balanced within the recommended range, test and add cyanuric acid to protect the chlorine and extend its lifespan. If you used stabilized chlorine, you may be able to skip this step.

Saltwater Pool Start-Up Chemicals Procedure: Step-by-Step Process

A saltwater pool has a slightly different set-up process involving adding salt and activating the saltwater chlorine generator.

Important note: If you have a concrete pool, PLEASE remember that you should only follow these steps after 28 days when your plaster has been fully cured, and the water has already been balanced for TA, calcium hardness, and alkalinity.

Step One: Turn On Filtration and Add Salt

After the 28 days and after you have already balanced your pool’s TA, pH, and calcium hardness as outlined above in steps 1 to 3, turn on the filtration system and add the correct amount of pool salt for your pool size. Then, run the filter for the next 24 hours until all of the salt has dissolved, which should take around 24 to 48 hours.

When picking what salt to use for your pool, it is important to use only sodium chloride (NaCl) salt greater than 99% pure. Do NOT use iodized salt or rock salt. Use pool salt specifically.

Once you pour the salt into the water, use a pool brush and net to help circulate the salt and speed up the dissolving process. The salt level of your pool should hover between 2,700 to 3,400 ppm.

Step Two: Adjust the Other Chemicals

After 24 hours, using a pool test strip or liquid test kit, check your existing TA, pH, and calcium hardness levels. If anything is out of range, adjust it as needed.

Step Three: Shock the Pool

Contrary to popular belief, saltwater pools actually use chlorine. To get your saltwater pool up and running, shock the pool to bring your chlorine levels up to speed. Make sure to run the filter to allow the shock to distribute.

Step Three: Activate the Saltwater Chlorine Generator (SWG)

Is everything balanced and within the proper range? Perfect! It is now time to let the SWG get to work. Switch it on according to the manufacturer’s instructions and allow it to run. When you’re first starting up as SWG, it’s important to keep an eye on the chlorine levels to ensure they remain within the recommended ranges. If not, adjust the SWG’s settings for higher or lower output.

Then, add cyanuric acid to maintain them at the optimal range.

How Often Should You Treat the Pool Water?

How often you need to treat pool water depends on how often it’s used, local weather conditions, the quality of water, and more. Here’s a general set of guidelines for how often you need to treat your pool with each chemical.

  • Chlorine: You should check and adjust chlorine 2 to 3 times a week. Chlorine is used up quite quickly due to sunlight and contaminants in the pool, especially in the absence of a stabilizer. So, keep a close eye on it.
  • pH: You should check and adjust pH 2 to 3 times a week as well. pH is subject to fluctuation due to weather conditions, such as rain or sunlight, as well as other chemicals.
  • Total Alkalinity: You should check and adjust your TA levels once a month. TA is more stable than other chemicals and requires less frequent adjustment than chlorine or pH, but it is still important to keep an eye on it.
  • Calcium Hardness: To avoid any unnecessary and avoidable damage to your pool, test and adjust your calcium hardness levels once a month, along with TA.
  • Pool Shock: You should shock your pool once a week to eliminate contaminants, kill burgeoning algae growth, and maintain chlorine levels. Switch off with a non-chlorine shock every other week.
  • Cyanuric Acid: Add as needed when using an unstabilized chlorine product.
  • Algaecide: Add as needed in conjunction with pool shock treatment if you’re experiencing a green pool or other signs of an algae infestation.
  • Pool salt (for saltwater pools): Add as needed. Salt does not break down or evaporate, nor does it get used by the SWG when generating chlorine. You will only have to add it if salt levels are diluted due to rainwater or a partial drain and refill. You can get away with testing it only every month or so.

Get My Free Pool Care Checklist

Download my free, printable pool maintenance checklist to help you accomplish regular pool care tasks for any type of swimming pool.

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Enjoy Your New Pool!

Now it’s time to cannonball into your pool! With your pool perfectly balanced, it’s time to jump in and have some fun. Remember: while your pool is balanced now, it’s just as important to maintain those levels throughout your tenure as a pool owner.

Do you have more questions about starting up your new pool? Send me a message; I’ll be happy to help you out.

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