For a thorough explanation of what affects pH and how to use muriatic acid or a pH decreaser to lower the pH in a pool, read this guide.

Does your pool’s pH have a problem? You may experience itchy eyes and skin, cloudy water, algae growth, and even damaged pool components if the levels remain high for an extended period of time. In order to restore your pH to normal levels, you must immediately add some pool chemicals. Muriatic acid or a pH decreaser like sodium bisulfate are the two options for lowering the pH in a pool.

A quick review of chemistry: the pH scale determines whether an object is basic or acidic. The pH scale has a range of 0 to 14, with 7 being neutral, anything below 7 being acidic, and anything above 7 being basic. The pH of your pool should be between 7.4 and 7.6 when it is properly balanced.

Even the swimmers themselves could have an impact on the pH level of the pool because everything that goes in has the potential to do so. Things like rain, mud, and debris in your water can also upset the balance. Even salt water systems produce naturally high pH levels. Due to the volatility of pH, it is crucial to routinely test the pH levels of your pool as part of your routine pool maintenance.

How Do PH and Total Alkalinity Affect Each Other?

Your pH levels and overall alkalinity are related. And your alkalinity aids in maintaining a constant pH level. The pH would fluctuate greatly without this buffer. The pH becomes unstable when your total alkalinity is too low. Additionally, if it rises too high, your pH levels may as well.

Because it can help bring your pH into range, adjusting your alkalinity before adjusting your pH is crucial. The range of 100 to 150 parts per million (ppm) is the ideal range for your total alkalinity. Use an alkalinity increaser if you discover that your total alkalinity is too low but your pH is higher than 6.8. Using a pH decreaser or pH reducer, such as sodium bisulfate, will lower both your alkalinity and pH if your overall alkalinity is too high.

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When is PH Too High?

pH measures the acidity of your pool’s water.

This scale ranges from 1 to 14, with 1 being very acidic and 14 being very basic. At a pH of 7, neutrality is located in the center.

A pH of 7.2 to 7.8, or slightly basic, is the ideal range for pool water.

However, too much basic water causes cloudier water, weaker sanitizer, scaling of pool surfaces, and general discomfort for your skin and eyes.

In order to avoid issues with your water, you should reduce the pH of your pool if it is higher than 7.8.

What Chemical is Best for Lowering PH?

A low pH chemical, also referred to as an acid, must be used to lower the pH in your pool.

The acids most commonly used in pools are:

• Muriatic acid (hydrochloric acid)
• Dry acid (sodium bisulfate)
• Sulfuric acid (sulphuric acid)

Muriatic acid is the most effective acid to use in most pools.

Sulfates are a chemical that both dry acid and sulfuric acid add to water, and at high concentrations, they can cause a number of problems.

Sulfates can damage concrete or plaster pool surfaces, be corrosive to metal pool parts and fixtures, and even degrade your saltwater generator if you have a saltwater pool, although they are less of an issue for vinyl pools.

As the purest and most effective acid for the job, muriatic acid lacks sulfates and other additives.

What Happens If Your Pool PH is Too High?

High pH is defined as a pH level of 7.8 or higher. Additionally, if your high pool water pH is neglected for an extended period of time, it may cause a variety of problems, including the deterioration of pool components and harm to swimmers.

Reduces Chlorine Effectiveness

The chlorine in your pool won’t be able to clean the water as thoroughly if the pH is too high. To achieve the same result as before, you’ll need to use more chlorine, which may alter the chemical balance of the pool’s other components. You might experience an algae bloom if chlorine isn’t working properly to kill microbes. Additionally, you might develop calcium buildup, which can result in cloudy water and harmed pool equipment.

Irritates Eyes and Skin

Swimmers may experience itchy, red eyes due to high pH. Additionally, they might develop skin irritability. So, contrary to popular belief, extremely high pH levels are what actually irritate the eyes and skin, not high chlorine levels.

Erodes Swimsuits and Swimmer Gear

Your swimsuits and goggles won’t last long in the high pH. The chemical imbalance may cause your swimsuit to fade or degrade the fabric over time to the point where you are unable to wear it. Goggles may become brittle and break more quickly than you anticipate.

Damages Pool Equipment

The high pH will cause calcium scale to accumulate on both your pool’s equipment and the walls of your pool. It’s possible that the accumulation will clog up machinery and obstruct water flow into and out of the pool. The pool pump may malfunction as a result of this and possibly become useless.

How to Lower PH With PH Decreaser (Sodium Bisulfate)

Sodium bisulfate, also known as dry acid, is the main ingredient in the majority of commercial pH decreasers, including pH Down and pH minus. They are more expensive than muriatic acid but safer and less corrosive to use.

On windy days, avoid adding it to your pool because it’s more likely that the powder will blow back into your face while using it.

1. Test Your Water

To determine how much you need to lower everything, start by testing your pH and alkalinity levels. Don’t worry if your total alkalinity is also too high; the pH decreaser will also lower it.

2. Measure Out the PH Decreaser

Calculate how much ph decreaser you need to use by reading and adhering to the manufacturer’s instructions.

You can start out with less and add more later. Keep in mind that if you add too much, it’s simpler to add more to restore your water balance than it is to change the chemistry of the pool.

3. Add the PH Decreaser to Your Pool

Near the return jets and in the deepest part of your pool, directly pour the chemical into the water. Run the pump continuously. Never include it in the skimmer. You might have to use a pool brush to help stir the water yourself if you own an above-ground pool.

4. Let the PH Decreaser Dissolve

Allow the chemical to dissolve and circulate throughout the water of your pool using the filtration system. If there are any undissolved clumps on your pool’s surfaces, you may want to brush them off because they can harm the walls and floor of your pool.

5. Retest Pool Water, Repeat as Needed

It’s not necessary to test your water again right away, but make sure to do so within 24 hours. Thank you if your pH and total alkalinity are within the normal range. The process should be repeated, though, if you discover they are still high.

How to Lower PH With Muriatic Acid

Muriatic acid, also referred to as hydrochloric acid, is an extremely corrosive and hazardous chemical. Therefore, you must take additional precautions if you choose this method to lower your pH. Wear clothing that completely encloses your body. Additionally, put on a mask, pair of safety glasses, and thick gloves to prevent inhaling fumes. You should stay away from a windy day even though it isn’t powder because of blowback and splashback.

1. Test Your Water

To determine how much to reduce both levels, test your pH and total alkalinity. Both pH and alkalinity will be decreased by muriatic acid. But they could diminish at various rates.

2. Measure Out the Muriatic Acid

Determine the quantity of muriatic acid required to bring your pH level back within the normal range. Start by adding 1 quart (1/4 gallon) of muriatic acid if your pH reading is greater than 7.8 and your pool is 15,000 gallons. Retest your levels an hour after giving the acid a chance to circulate. Add one cup of muriatic acid at a time to a smaller pool to start. Add more as necessary after one hour of waiting. For information on how much muriatic acid to add based on the pH of your pool and its size, see the chart below.

3. Add Muriatic Acid to Your Pool Water

Since this substance is acidic, if it begins to assemble in one area, it could harm your pool’s liner. So make sure your filter is always running, ideally on the circulate setting, to keep your water flowing. Commence slowly and keep in mind that you can always add more acid later.

If you first dilute muriatic acid in a bucket of water, handling it will be simpler and safer. Always follow the manufacturer’s instructions, but the ideal water to muriatic acid ratio is 10:1. Additionally, add the water first, then the muriatic acid, to prevent splashback.

• Method One: Muriatic acid should be added in a small, steady stream into the deep end of your pool while the pump is off. By doing this, it is ensured that the acid will sink to the bottom and not float around at the pool’s surface. In order to circulate the acid through the water, first turn on your pump.
• Method Two: Pour the acid into the pool close to your return jets gradually, then turn on the pump to circulate it. For above-ground pools, add the acid gradually while circling the pool to prevent concentration in one area.

Check out our guide if you need additional assistance adding muriatic acid to your pool safely.

4. Let the Muriatic Acid Dissolve

Allow the chemical to dissipate while keeping the filter in your pool running, preferably on circulate. Within an hour, it ought to be gone. However, if you had to add a significant dose, it might take longer.

5. Test Your Water Again

After a couple of hours, recheck the pH and alkalinity. If the levels are still high, repeat the procedure while gradually introducing more muriatic acid.

If you’ve only added a little muriatic acid, you should be able to swim after the pool has been circulated for one hour. Wait 24 hours before retesting your water and going swimming if you’ve added more than that.

What If the PH and Alkalinity Won’t Balance?

After adding pH decreaser or muriatic acid, it’s not unusual for your alkalinity or pH to still be out of balance. Your alkalinity is still too high, even though you could have added enough muriatic acid to lower the pH. Alternately, you may have added enough acid to lower your total alkalinity to the required level, but your pH has now dropped.

You can add soda ash to your water to help raise the pH and alkalinity levels if they are both too low. What if, however, you only need to adjust your pH?

With the aid of pool aeration, you can raise pH levels without affecting alkalinity. Using a pool aerator or fountain will produce bubbles that aid in the water’s carbon dioxide outgassing. Your overall alkalinity won’t be affected as the pH rises as carbon dioxide leaves the water. Additionally, you can add more acid to the water while aerating it to maintain a high pH if you need to lower the alkalinity.

Why High PH is Bad News

It’s not surprising what happens when pH is out of balance given how crucial pH is to the chemistry of your pool.

These are the side effects of pool water that’s too basic (high pH):

• It degrades your hand sanitizer. As your pH rises, your water is less protected against contaminants like algae because chlorine’s sanitizing power is strongest at lower pH levels.
• Your surfaces are scaled by it. Calcium scale, which stains surfaces, results from the calcium in your water dissolving in high pH. Having high calcium levels exacerbates this effect.
• Your water becomes cloudy as a result. The water in your pool may appear murky or cloudy as the pH rises and calcium leaves the solution, particularly if the calcium hardness is high.
• It hurts the skin and eyes badly. Water with a very high pH can irritate your skin and eyes, but the main cause is frequently an accumulation of used chlorine (known as chloramines) in the water.
• It makes pH adjustments more difficult. Since alkalinity is a pH buffer and high alkalinity results from high pH, adjusting your pH level will become more difficult as a result.

Why Your PH is High (And How to Prevent It)

If you’ve tested your water and the results show a high pH level, it was probably caused by one or more of the following:

• Your pool was shocked. Calcium hypochlorite, the type of pool shock that is most frequently used, has a very high pH. It’s typical to notice an increase in both your calcium hardness and pH levels.
• You have algae. Because carbon dioxide is an acidic substance, algae slowly raise the pH level of the water by consuming it. This process is similar to water aeration.
• You unintentionally used a pH-increasing substance. High pH chemicals with other uses, like soda ash and borax, are sometimes used in swimming pools. In order to remove pool stains, for instance, use borax.
• You made use of acidic water. Always check the pH of the source water before making any assumptions, whether you’re filling or topping off your pool. It’s possible that well water is overly saturated.
• Water features are present. The movement and splashing that water features produce in your pool speed up aeration (the release of carbon dioxide), which ultimately raises pH.
• You have a salt pool. Saltwater generators produce a lot of bubbles as salt is converted to chlorine, which serves as another form of aeration, raising the pH level similarly to how water features do.
• Your swimming pool was replastered. For up to a month, fresh plaster releases calcium hydroxide. Your pH will naturally rise when this substance is absorbed by the water because it has a pH level of 12.
• It’s high to be alkaline. The more total alkalinity you have, the more basic your water will eventually become because it is a measurement of all dissolved alkaline substances in the water.

What Goes Up, Must Come Down.

It’s important to always keep in mind that a high pH level is bad for your pool, so you should take action to detect and address it.

The good news is that you can quickly lower the pH level in your pool using a measured dose of muriatic, dry, or sulfuric acid as long as you have a test kit on hand and a calculator to boot.

Frequently Asked Questions About How to Lower PH in a Pool

Do you need assistance lowering the pH in your swimming pool? Here are some frequently asked questions and their responses.