How to Lower PH in Pools: Your Guide

If we asked you how sure you are that you drink clean and pure tap water, would you answer with 100% certainty?

Well, if your answer involves a “Yes, it is clean and pure,” then you need to do some water purity fact-checking. That’s because even the nine states that have the safest drinking water still have some level of lead in their supply.

That’s right. The Flint, Michigan problem with lead contamination is only one of the thousands of others.

But that’s not all you should worry about. How to lower pH in pools is as big a water-related concern you need to address. Especially if you’re one of the lucky owners of the 10.6 million pools all over the United States.

What exactly is pH though and why do you need to control its level in your pool water?

We’ll answer all these and more, so keep reading!

The Chemistry of Your Pool Water

To understand pH and why you need to keep it low (or bring it up), we first need to talk about pool water chemistry. It is, after all, the key to proper pool maintenance, which is essential to safe, healthy, and fun swims.

Your priority is to keep the water in a balanced state, which means ensuring correct water balance and sanitation. Note that crystal clear water doesn’t guarantee safety and healthy water.

Water Balance

pH sits at the very top of pool water chemistry hierarchy. That’s because it influences all the chemical balances in the water.

At its core, pH refers to the scale of measurement for pool acidity and level of alkalinity. It’s a range starting from 0 (acidity) to 14 (alkalinity). The lower it is, the more acidic the water, and the higher it is, the more alkaline the water.

Although 7 is the neutral pH level, it’s best to keep your pool water around the 7.2 to 7.6 range. One reason is because it’s the level least irritating to the human eye. It’s also the best level for free chlorine use as well as keeping scale formations and corrosions at bay.

What happens though, if your pool water has a pH level higher than 8?

First off, the chlorine you put in the water won’t be as effective in sanitizing it. The pool water will also become cloudy, soon followed by scale formation and staining of the pool walls. Too much alkalinity also affects the pool filter, “choking” it and rendering it efficient.

The worst part is, you may experience serious eye and skin irritations due to the high pH level.

On the other hand, if your pool water pH level falls below 7, you’ll be swimming in pool acid. This means eye and skin irritation, for starters.

As if that’s not enough, the too acidic water also starts corroding your pool heater, especially if it’s not made of Titanium, as well as other metal fittings. From here, the dissolved metals can stain your pool walls. Also, leaving your pool water with a too low pH can damage your pool liner.

Water Sanitation

You need to sanitize your pool water to ensure its safety for use. Failure to do so will make it a breeding ground for dangerous bacteria.

In the U.S., chlorine is the most common chemical used to sanitize and disinfect swimming pools. But like any other chemical, you need to know how much chlorine to use. Otherwise, you can turn your pool water into something as powerful as bleach.

Here are some of the most important must-haves to keep your pool sanitized and safe:

  • Disinfectants and sanitizers to get rid of harmful organisms
  • Sodium carbonate or Soda Ash (pH Plus) to boost pH level
  • Sodium bisulphate (pH Minus) to lower pH in pool water
  • Chlorine stabilizers to help maintain optimal chlorine levels
  • Algaecides to prevent algae growth
  • Pool filters to keep those foreign materials out of the water

As a pool owner, you want to make sure your investment pays off and allows you and your loved ones to enjoy the benefits of swimming. More importantly, though, you don’t want it to put anyone at risk of pool-water-related health problems (think diarrhea and infections aside from eye and skin irritations!).

All these said, you need to pay more attention to your pool’s water balance and sanitation. Let’s now take a look at how to achieve optimal pH level.

How to Lower pH in Pools

Aside from the above-mentioned effects of high pH, you also have algae growth to worry about. That’s because of the chlorine not working to its full capacity. You may also experience burning sensations in your eyes and nose, not to mention itchiness and dryness of the skin and scalp.

To avoid all these, one way on how to lower pH in your pool water is to add a pH-reducing acid to it. You have several options, including the following chemicals:

  • Muriatic acid with a 30% to 35% liquid hydrochloric acid content
  • Sodium bisulfate in granule or powder form
  • pH Minus (dry acid)

Before adding any of these substances though, you first need to determine the volume of your swimming pool. This is important because pool volume influences the amount of water treatment solutions you should use.

Pro Tip: You may want to calculate the volume using liters than gallons, as this will make it easier for you to quantify how much chemicals to use.

If you know the volume in gallons, then you only need to multiply that by 4.5. This’ll give you an estimate in liters. Say your pool volume is 1,500 gallons, then it’s approximately 6,750 in liters.

When using pH Minus (dry acid) to bring down the pH level of your pool water, keep it to 10 grams a day for every 1,000 liters. This means that, for a 6,750-liter pool, you need about 67.5 grams of dry acid. Keep adding this amount until the pH goes down to at least 7.6.

Two Other Important Considerations for Optimal pH

There’s a little more to lowering (or increasing) your pool water’s pH level. You also need to consider Total Alkalinity (TA) and water hardness, as these two also affect pH levels in pools.

Total Alkalinity

TA refers to how much water can resist changes in the pH. It measures the quantity of alkali in the water, including hydroxides, bicarbonates, and carbonates.

You need to keep this at a range of 80 to 140 parts per million (ppm) to ensure it doesn’t disturb the pH balance.

Too high a TA level, and you’ll have a hard time adjusting the pH level. In most cases though, excessive TA levels cause a significant increase in pH levels. From here, your pool disinfectants will become less effective and scale formation begins.

Pool water with a TA falling below 80 also makes it difficult to keep the pH level stable. The pH also drops quickly, which may result in corrosion.

If your pool has a TA level too high, diluted muriatic acid can help bring it down. As for increasing TA, you’ll find products like T.A. Plus that can help. Make sure you check and follow the dosing instructions!

Water or Calcium Hardness

Water hardness refers to the amount of dissolved calcium present in water. In swimming pools, the water hardness should stay within 200 ppm.

Go beyond this, and scale formation will start. Whereas too soft water can corrode your pool walls and equipment.

The good news is, you can easily increase water hardness through products like Hardness Plus. It’s a little more difficult when you have too much dissolved calcium though, since you’d have to dilute your pool water.

What About Low pH?

If your pool water problem is due to too low pH, then you’ll have issues like pool plaster and grouting erosion, metal corrosion, and staining among many others. You may also notice your swimwear thinning or fraying out! It can also take a toll on your health, the same way as having high pH does.

So how do you go about solving this?

For starters, you can add alkali or a base chemical designed to increase pool water pH level. Most pH increasers use sodium carbonate as their active ingredient. Keep in mind that dosage also depends on Total alkalinity, so be sure to follow the chemical’s instructions to a T.

You’ll also notice that your pool’s pH goes down after heavy rains. This said, you’d want to check the pH level after several days of rain before getting into the water.

Keep Your Pool Safe and Healthy with a Balanced pH

Now that you know why and how to lower pH in pools, make sure you practice and master it! This way, you don’t have to worry about that investment you’ve most likely spent $22,000 on!

More importantly, though, maintaining proper pH balance prevents you from getting dry skin, red eyes, or a burning nose after taking a dip in your pool.

Looking for great pool filters and accessories that will save you money? We’ve got you covered with our large inventory!

1 thought on “How to Lower PH in Pools: Your Guide”

  1. Hi, thanks for this information, it is very helpful. Quick question, we just purchased our home, and the water comes from the well. We just emptied the pool, had it cleaned then spent 3 days refilling it; it is 20’×40′. The test strip has the water at the hardest level. Are there chemicals I can use to soften the water?

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