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How Much Bleach to Add to a Pool to Make Swimming Safe?

You may be asking yourself how much bleach to add to a pool to make swimming safe. When you get a new pool, at first the excitement is too much to handle. That is until you come to the realization that is the headache of keeping pool water clear.

People on social media make maintaining a crystal clear pool look easy. However, you may find that it is costly and frustrating to maintain a crystal clear swimming pool. Luckily, there is a cost-effective alternative that can make your life easier.

Most people chose chlorine as a pool sanitizing agent. When you add chlorine to pool water, it kills microscopic organisms in the water that cause the pool to become cloudy. Bacteria such make the water unsafe to swim in.

It is easy to understand the chemistry behind how chlorine breaks down bacteria. Chlorine destroys microbes by using their negative charge to rip through the outer membrane rendering it useless.

Liquid bleach or hypochlorous acid is the most popular form of chlorine. When the liquid bleach hits the water, the molecules turn into negatively charged ions and immediately get to work cleaning the bacteria out of your pool.

How much bleach should I add to my pool?

So, how much bleach to add to the pool? First, you need to know how much bleach to use. To do so, you need to know the chlorine levels of the pool. Get yourself a chlorine testing pool kit and follow the manufacturer’s instructions.

You want to have a chlorine level of 1-3ppm so you can make sure that your water is safe for swimmers and free from contamination.

Clorox is considered to be the most common bleach product that is used for pools. It has a 5.7% concentration, so if you have a 5,000-gallon pool, you will be using 3 cups or 24 oz to raise the chlorine levels.

If you do not know how many gallons your pool holds, just multiply the length, by the width, and finally by the relative depth of your pool and you will have an estimated volume. If you have a round pool multiply that volume by 5.9, if you have an oval pool multiply by 6.7 and for a rectangular pool multiply by 7.5 gallons. The final result will be an estimate of how much water your pool holds.

If you need to calculate how much bleach or Clorox you need to shock your pool, you will have to use 1/2 gallon of bleach per 10,000 gallons of water to raise the chlorine levels by 5 ppm. If you are just trying to raise the chlorine level by 2.5 ppm, then you will have to use as much as a ¼ gallon of bleach per 10,000 gallons of water. Use this basic math to figure out how much ppm you have to raise your pool by and go from there. Make sure to continually test the pool water.

How do I add bleach to the pool water?

Most pool stores do not suggest using simple chlorine as a bleaching agent. They want you to use their products for adding bleach to the water. Most pool specialty stores will sell slow dissolving tablets of chlorine that when combined with other ingredients, stabilize the chlorine, so it releases slower, thus making it last longer. Although this may seem like the easier solution, stabilizing bleach greatly reduces the effectiveness it has on killing the microbes that need to be removed from your pool.

The chemicals that are used in these tablets, such as dichlor, break down very slowly and difficultly and overall you cannot control how much of it is going into the water. Therefore, the new chlorine that is added via tablet will attack the dichlor and immediately be stabilized and will not attack the bacteria that you are trying to eliminate.

The tablet is rendered effectively useless, and in a few weeks, the result will be a cloudy pool. More than likely, you will be stuck in a situation where the pool store will sell you additional expensive products that will not fix your problem. This is a costly mistake.

As stated, the easiest way to make sure you have a clear and healthy pool is to use liquid bleach. The reason this is true is it does not have stabilizers that will make the chlorine become ineffective at sanitizing the water. You will have to make small, daily adjustments to the water. This may seem like a lot, but a few minutes a day will result in a crystal clear pool and a constant and stabilized condition that is cheaper and easier to manage.

Do not forget, however, when you add liquid bleach to a pool, you still have to add a small amount of stabilizer, so the sunlight doesn’t eliminate the bleach molecules immediately. This step should not be too difficult since you are controlling the amount of stabilizer; you should be able to prevent over stabilization.

You can add the stabilizer when the pool is first open and then likely not again for a few weeks or months. Just remember to check the levels of your pool regularly as it is your first defense in water sanitation.

Once your pool is stable, it will protect the amount of bleach it needs to while allowing non-stabilized chlorine to do its job. This results in the maximum effectiveness of the chlorine and a beautiful pool. By following these simple steps, you can rest assured that you will have a crystal clear pool without having to break the bank!

Josh Hurd


Saturday 25th of June 2022

I had about 350-400 gallons of water in the bottom of my pool with algae, mosquito larvae and other junk in it from over the winter, I put a gallon of bleach in it and I am filling it up now, to 1,500 gallons, sounds like I put way too much bleach, any idea how I can figure out how long it would take to stabilize/ how much stabilizer I might need to add manually? Or any other suggestions?


Sunday 12th of June 2022

We have a 300 gallon kitty pool how much Clorox bleach should we put in it?


Sunday 12th of June 2022

@Larry, It makes 1.44 oz.