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Home Pools Pool Chemicals How to Lower pH in Pool + Top 3 Efficient Products [2023]

How to Lower pH in Pool + Top 3 Efficient Products [2023]

You need to lower the pH in your pool, but you don’t know how? We are here for you. Just read this article to get all your questions answered and tried-and-true products.

​​You love your pool, but not balancing water chemistry, don’t you? Well, I can’t blame you for that — I like things to work on their own. Unfortunately, it doesn’t always happen; for example, your pool pH level is unlikely to drop if you do nothing (usually).

The good news is that lowering pH is pretty straightforward — sodium bisulfate or muriatic acid will do the job. The not-so-good news is that each product has its pitfalls, which we will tell you about today. Stay tuned to find out which product will best lower the pH in your pool.

Read also about the three proven methods to raise pH in our other article.

​Comparison Table

If you already know how things work and just want to see the products I recommend, please do. I researched to find out which products are safe and effective enough and got three favorites. These models have the highest ratings and the number of reviews, and on top of that, I studied all the reviews for each (over 300 total) and determined the winning categories for all of them.

Clorox Pool & Spa pH Down
The fastest effect

✓ Quickest lowering pH (in an hour or even less)
✓ It prevents the formation of limescale
✓ Clear and helpful instructions

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SpaGuard pH Decreaser
The best value for money and ease of use

✓ Efficient at 9 out of 10
✓ Simple and user-friendly
✓ It prevents cloudy water in pool

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Acid Blue Muriatic Acid
Acid Blue Muriatic Acid
The safest muriatic acid to lower pH

✓ Three times safer than other muriatic acids
✓ Does not irritate the skin or eyes
✓ No scent

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Why can the pH level be too high?

❗ A brief primer:
pH measures the activity of hydrogen ions. It is the main indicator determining the acid-alkaline balance.

A hydrogen value above 7.4 indicates an accumulation of alkaline above the recommended amount in the water. This occurs naturally over time (a few days), due to numerous swimmers or improper operation of automatic water treatment facilities.

Why high pH can be dangerous

We don’t want to scare you for anything, so do not be afraid, you won’t die from high pH in your pool. However, it will create some discomfort.

Increased pH in the pool water causes:

  • Calcium deposits on equipment, liners, and pipes;
  • Accelerated reproduction and growth of microorganisms;
  • Irritation of the skin and mucous membranes of swimmers;
  • Increased maintenance costs due to the ineffectiveness of chemicals in an alkaline environment.

Visually, an increase in pH is manifested as turbidity in the pool water. Fine flakes appear, some of which precipitate on the bottom and walls of the basin.

How to lower pH in the pool

There are two common options for lowering pH: sodium bisulfate or muriatic acid. The question is, what is the difference between them and which is better to use?

Sodium bisulfate VS Muriatic acid

Both sodium bisulfate and muriatic acid are effective when it comes to lowering the pH level. However, there is a difference between the two, which is easiest to demonstrate with a small comparison table:

Sodium bisulfateMuriatic acid
What is itSodium bisulfate is also called dry acid. It is safer than muriatic acid, but also more expensive (one of the reasons — you need more of it than muriatic acid).Muriatic acid looks like a colorless solution with a pungent odor. It is a strong, poisonous acid that is used to lower the pH and alkalinity in a swimming pool. It is also used to clean up stains.
How to use✓ Test the water to find out the pH level
✓ Read the instructions to determine how much sodium bisulfate is needed
✓ Pour the product into the pool next to the return jets without turning off the pump
✓ Test your water after an hour or overnight to see if the pH is back to normal
✓ Test the water to find out the pH level
✓ Read the instructions to determine how much muriatic acid is needed
✓ Take a bucket, add water, then an acid (10:1 ratio)
✓ Add this mixture next to the return jets without turning off the filter
✓ After one hour, recheck the pH level
Dosage comparison10.5 pounds (168 oz)one gallon (128 fl.oz.)
Price range$$$
Best fit forfiberglass or vinyl poolgunite pool

Which is better?

In most cases, you will probably like muriatic acid more — it’s cheaper and a little more powerful than the second option. Although, much depends on the pool material — some people are safer using sodium bisulfate and some people are safer using muriatic acid (see table).

Detailed review

Clorox Pool & Spa pH Down — the fastest effect


  • The fastest effect 
  • Not only balances pH but also prevents scale
  • It’ll help you to preserve the pool and equipment
  • Directions are clear and helpful


  • It may not be very convenient to measure the dosage of the product, since it is listed in oz.

If you’re looking for a relatively inexpensive and easy way to quickly lower the pH in your pool, consider Clorox Pool & Spa pH Down. This is a sodium bisulfate-based pH reducer that looks like a granular powder. 

More than 90% of the 4,000 users were successful in lowering pH with this product. There are exceptions when it doesn’t work (then we suggest you try Acid Blue Muriatic Acid (review)), but in most cases, Clorox will be enough for you. Just follow the instructions and don’t forget to test the water after balancing.

A nice bonus: Clorox has a special app that you can download to your phone to make monitoring your water chemistry balance easier and more enjoyable. 

You may have trouble measuring, but here’s a chart to help you convert ounces to cups if you need to:

Ounces to cups conversion table
Ounces to cups conversion

SpaGuard pH Decreaser — the best value for money and ease of use


  • The best value for money according to users
  • Does a decent job lowering pH and alkalinity levels
  • Easy to use and store
  • Prevents cloudy water in a pool


  • If your pH is too high (over 9.0) it might not be as effective as muriatic acid

Another quality product in case you’re not too fond of Clorox or a form of their pH reducer is SpaGuard pH Decreaser

This product comes in granular form and is probably even easier to use than the previous option. The non-obvious pluses it has: no odor and rapid dissolution in water. 

This product costs more than Clorox, but its effectiveness and ease of use justify its price — 94% of users were satisfied with the result and the appearance of their pool.

Acid Blue Muriatic Acid — the safest muriatic acid to lower pH


  • The safest to use, compared to other muriatic acids
  • No burning on eyes or skin 
  • It is economically consumed
  • Doesn’t have any odor
  • Does a decent job lowering pH


  • It is more expensive than the regular muriatic acid you find in the store, but at the same time, it is just as safe.

If you decide that muriatic acid is better for you, Acid Blue Muriatic Acid is the best choice in this category. Muriatic acid is generally considered more dangerous, but if you follow the instructions, it is worth it.

It will not sting your eyes or skin (do not be afraid) and is quite economical to use, although you will not save a lot of money. But you pay for what you get. 

How do you make sure this product will be safe for you? You should use protective equipment (gloves, goggles) and use the bottle as carefully as possible so that the acid does not get into anything but the pool water. Unfortunately, this product is quite poisonous and will kill your grass if it gets there.

Natural ways of decreasing pH VS chemicals

The man holding the indicator of pH levels in the water

There are at least four ways you can try to lower the pH naturally. However, they do not always work or suit you.

💧 One such way is to install a distilled water system. This is a good idea if your area has hard water. Distilled water is almost pure, with no metal or mineral impurities and a pH of 7. 

The downside to this option is that you will have to fiddle with doing the trick, and every time you want to drain and refill the pool, you will have to figure out how to get water from home to the pool. By the way, even if you install a distilled water system, you will still need to test the water regularly.

✓ The second way is essentially part of pool maintenance, namely cleaning. You need to clean the pool regularly so that foreign bodies (even leaves) do not affect the pH level. If you don’t have time to do this, consider hiring a pool maintenance service.

🙌 The third option is to leave everything as it is. Perhaps after some time, the pH level itself will come back to normal. Try not changing the water and just wait, then test it again. Sometimes this can work, but again, it’s all individual.

🔥 The last way is to buy a heater. If you heat the water, the pH will decrease over time. Why? Warm water dissolves substances such as calcium carbonate, which helps to lower the pH and increase the acidity.

So what’s better?

Natural pH-lowering options are safer in terms of affecting the skin and everything else, but on the other hand, they are not always effective. You have to assess the situation objectively. For example, if you know that your pH often rises because of the area you live in, it’s probably worth using chemicals (or installing a distilled water system if you’re not too lazy to deal with it).

If the problems are infrequent, maybe regular cleaning will be enough, or just “wait” for a while (if you have time). Anyway, chemicals are a quick and effective way to lower your pH, whether it’s sodium bisulfate or muriatic acid.

How to prevent high pH in your pool

The most essential thing you can do to control pH is to test your pool water regularly. The test strips are easy to use and affordable, and all you have to do is remember to use them.

Besides, do not forget about quality pool maintenance: water changes, disinfection, and checks of the efficiency of equipment — pipes, filters, and pumps will help to avoid increasing pH.

prevent high pH in your pool


So, balancing the pH is critical to keeping your pool pleasing to the eye and safe to use. There are many ways to lower it, both naturally and with chemicals. You can try virtually any of them, but natural approaches won’t always be able to guarantee you results. 

If your usual pool care routine has not helped bring your pH levels back to normal, we still suggest trying sodium bisulfate (for fiberglass or vinyl pools) or muriatic acid (for gunite pools and when all else fails). Also, test your water regularly (at least once a week) so you always know if everything is okay with your pool. Have a great swim!


🧐 How do I lower the pH in my pool naturally?

There are four ways to lower the pH naturally: buy a heater, put in a distilled water system, clean the pool, or leave it as it is and just wait (not 100% warranty that it’ll work).

📈 What happens if the pH is too high in a pool?

Visually, an increase in pH is manifested as turbidity in the pool water. Fine flakes appear, some of which precipitate on the bottom and walls of the basin.

⌛ How long does it take for pH to lower in the pool?

On average, you should wait 2-4 hours before testing the water again if you use natural ways and 15-30 mins with chemicals.

🏊‍♂️ Can you swim in a pool with high pH?

We cannot forbid you to swim in water with a high pH, but we warn you that you are unlikely to enjoy it because such water can irritate your skin.

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