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How Much Muriatic Acid to Add to Lower Alkalinity in Pool

Do you know how much muriatic acid to add to pool? I know the same question was what brought you here in the first place.

In this article, I will answer your questions and other pressing issues relating to the alkalinity of pool water.

A few acids like muriatic acid can clean the swimming pool because of their cleaning properties. These acids are well known to pool cleaners.

How much muriatic acid does one need to add to a pool? If the pH and alkalinity of a pool or spa are high, muriatic acid can reduce it. Therefore, the quantity of muriatic acid you need for your pool or spa depends on the volume of water (gallons) and the pH reading.

The benefits of adding muriatic acids are not only to your pool investment but to family and friends who come in direct contact with the pool. If the alkalinity level is left too high, the pool gets:

  • Irritating to the eyes and skin of the users.
  • Lack of Chlorine.
  • Unclear Water.
  • Scaling (deposits on the surface of your pool).

Since we’ve established why Muriatic acid gets added to pools. Let us see how much to add, how to add it, and when you should add, and also answer other questions from pool owners regarding the use of muriatic acid.

What is The Meaning of pH?

“pH” is an acronym for “power of hydrogen. It is the amount of Acidity/alkalinity in water. It can also be the amount of hydrogen ion concentration in water.

“pH” level ranges from 0 to 14. The smaller the pH number measured on the scale, the more acidic the solution is. And, the higher the pH number measured, the more alkaline it is.

Therefore, the comfort of swimmers depends on the pH Measurement of the pool water. They may experience itching when the PH of the pool is not balanced.

 The Cause of Unbalanced pH in Swimming Pool

Several causes affect the pH balance of your swimming pool and make it unbalanced. They include:

  1. Body waste from swimmers
  2. The source of your water
  3. Some disinfectants
  4. Water treatment chemicals
  5. Dust and debris
  6. Evaporation
  7. Aeration of water

Why Should Pool pH Need to Be Balanced?

The pH level of your pool needs to be balanced so that swimmers do not experience any discomfort like itching, hurt in the eyes, etc. Also, a controlled pH help to prolong the life span of the material that makes up the pool.

How to Control a Pool’s pH/Alkalinity?

Here is what to do to control the pH/Alkalinity of your pool.

  1. When the pH/Alkalinity of your pool is high, and it needs reducing. A simple solution is to add muriatic acid, also known as hydrochloric acid.
  2. But, if the pool’s pH is low, you need sodium carbonate (soda ash), while if the alkalinity is low, Sodium bicarbonate (baking soda) will add to raise the pool’s pH.

I hope you can spot the difference with regards to pH or Alkalinity control in pools?

How Much Muriatic Acid to Add to Pool to Lower Alkalinity

The amount of muriatic acid to add to a pool depends on the size of the pool and quantity of water, and how high the pH is.

An example, if you have a pool of 20,000 gallons of water with a pH of 7.8-8.0. You need about 1 quart or 32 oz of muriatic acid to add.

To know how much muriatic acid to add to the pool. First, you’ve to know the pH of your pool using test kits or sensors. Secondly, you need a pool alkalinity calculator to calculate and quantify how much muriatic acid to add to the pool.

To determine your pool’s pH, you need to use a test kit or pool sensor device. Test strips give an estimate but not the exact reading. While test kits like Taylor’s Drop Test give a better pH reading of your Swimming Pool.  Check Taylor’s Drop Test Price.

Also, an acid demand test can help determine the total alkalinity level of your pool. Now with the readings you’ve, you can calculate a more accurate dosage of muriatic.

Pentair Acid Demand & Alkalinity Indicator Solution is one such test kits that help you with such task. Check Price Here.

Acid Pool Calculator

Using an acid pool calculator is one of the best ways to determine how much muriatic acid to add to a pool to lower the alkalinity of the pool.

To use an online muriatic acid pool calculator. You’ll have to key in the following parameters to get the amount of acid suitable:

  1. Gallon/quantity of Water 
  2. Current pH
  3. Desired pH

To find out how to calculate your gallons and how to use a muriatic acid pool calculator, read more here*.

The current PH can be measured by a pool sensor device that gives a definite reading, unlike a test strip that only tell high and low.

If the desired pH is constant, the ideal range is (80-120 ppm). It depends on what you want to achieve (lower or higher alkalinity).

A pH sensor makes it easier to maintain the proper pH level of your pool and spa. It also helps protect the life longevity of the materials used in making your pool and spa.

Investing in a product will save you money, stress, and time involved in testing the pool’s pH.

PoolWarden pH Sensor - how much muriatic acid to add to pool
PoolWarden pH Sensor

If you want to do it without using the online muriatic acid pool calculator, then you’ll have to add the acid bit by bit while testing to see if it’s back to normal. Of course, this will take more time if you’re adjusting for a big pool.

Note: The desired PH is between 7.5 – 7.6.

How to add Muriatic acids to pool

The steps can be a bit hard to follow if it’s your first time, but you’ll get used to it over time.

1) Know the PH of your pool: Of course, it’s the result of testing your pool’s PH that warrants adding acid. There are test strips specifically made to test the pool’s PH, but for more accuracy, you can turn to a pool sensor that does the testing in real-time and more accurately.

2) Get the quantity right: If the test turns out your pH is higher than what’s normal – it’s time to add muriatic acid. But you don’t just go on and add you need to know the amount suitable to your pool’s size.

For many pool owners, they know how many gallons of water fill the pool to the brink. If the pH is known, then one problem is solved, but if it’s not known, then you’re going to have to measure it.

To get the pool size in gallons, multiply the length by the width and the depth (length*width*depth) that will give you the number of gallons your pool takes.

Note: This is assuming it’s a rectangle pool shape. But, If it’s not, the pool’s volume has to be calculated separately using the division as different shapes.

3) Protect yourself: Put on protective clothing as we’re dealing with acid that can damage our body. Get yourself covered without leaving anything out. Wear shoes, an apron, long-rubber gloves reaching your elbow.

Avoid breathing the muriatic acid as it’s harmful.

4) Mix the acid: You can’t just add the acid to your pool directly. First, you have to dilute it with water.

Our choice of container is plastic and should always be. Whatever amount of muriatic acid you’re to add, the water in the container should be 10 times the acid’s volume. Add the acid slowly and also stir slowly. Be careful not to spill or splash as acid is harmful to most surfaces. If an accident happens, make sure to clean it up and wash it with water.

5) Add to the pool. Before adding the muriatic acid get the pool filled. Pour the acid mixed with water close to the walls of the pool. Move around the pool as you do this.

The pump should be on this will allow proper mixing to avoid “pooling” at the bottom. One of the risks of not allowing the pool to mix well. The acid settles at the bottom of the pool which can be damaging to the pool floor.

Let’s Consider Other Related Questions:

How Long After Adding Muriatic Acid Can You Swim?

Since we want the acid to get mixed with water properly, I suggest waiting for 30 minutes to 1hr is fine. During this time, the pump should be left running.

When to Add Muriatic Acid to Pool?

We all know that muriatic acid can reduce the pH of the pool. So, you only add this acid when the pH of your pool and spa is higher than 7.6.

How Often Should One Add Muriatic Acid?

There’s no duration or scheduling involve in adding muriatic acid to your pool that you must keep. You can add every time the pH level indicates (when pH is high).

Is Muriatic Acid and Hydrochloric Acid the Same?

Muriatic acid is also known as hydrochloric acid. Both are of the same chemical composition.

Bottom Line

In this post, I have shown how much muriatic acid to add to a pool and how to add the acid safely. In addition, I have answered other related questions regarding the use of muriatic acid.

Please take cautionary measures in dealing with this acid, as it can cause damages to the skin and surfaces if not properly handled. 

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