How to Lower pH Level in Your Pool Safely

Maintaining the appropriate chemical balance in your pool is no easy task. Many homeowners struggle with pool chemistry and at the top of their problems is how to balance pH level.

A spike in your pool’s pH can cause many issues, be it eroding equipment or causing skin irritation. Luckily, there are a few ways to fix this problem. In this extensive guide, I detail the safest way to lower the pH level in your pool.

What Causes High pH Levels?

The normal pH of pool water is between 7.2 and 7.6, but I usually consider 7.4 as the optimum pH. However, you shouldn’t worry if this value isn’t exactly 7.4. It’s perfectly normal for your pool’s pH to occasionally fluctuate.

You should be concerned if the value frequently goes beyond 7.8. High pH levels mean your pool’s water is very alkaline. Alkaline water can cause a number of problems in your pool, so it is important to stay on top of your pH level.

Water pH is extremely unstable, and many factors contribute to its surge. Below are the most common causes.

Pool Shock

Shocking your pool is vital for sanitizing the water, but you should only do so when necessary. Over-shocking is possible and can cause chemical instabilities in your water. Pool owners use chemicals like calcium hypochlorite, sodium hypochlorite, and sodium Dichlor.

If you use calcium hypochlorite (cal hypo), you need to be extra careful. Although cal hypo is neutral, its pH can surge past 10 when mixed with water.

Runaway Alkalinity

High total alkalinity (TA) levels can raise your swimming pool’s pH. TA functions as a buffer that inhibits pH fluctuation. However, you should carefully pick the chemicals you use to increase the alkalinity of your pool.

Most individuals use sodium carbonate (soda ash) to increase TA. The problem with sodium carbonate is that it has a high pH of 11.3-11.6. This range may increase the pH levels of your pool.

Improperly Measured Chemicals

To maintain a pool’s chemical balance, you have to use the right chemicals and, more importantly, the right amounts of chemicals. Excess quantities might cause either high or low pH levels.

Carbon Dioxide Loss

From my experience, the loss of carbon dioxide (CO2) from pools can account for high pH levels.

Carbon dioxide transforms to carbonic acid when it dissolves in water. The pH of this acid is low, meaning it lowers your pool’s alkalinity.

The CO2 concentration in water should be similar to that in air. Carbon dioxide dissolves into and out of the pool’s water until an equilibrium is reached.

The presence of algae in water primarily causes carbon dioxide loss. Algae consume CO2 and, in doing so, prevent the formation of carbonic acid.

Other factors that may cause CO2 loss in pool water include splashing and aeration.

What Happens If pH Is Too High?

You’ll encounter a lot of problems if your swimming pool’s pH constantly rises.

Unhealthy to Swimmers

High pH levels in a pool can be a health hazard to swimmers. Swimmers might experience:

  • Red, irritable eyes
  • Dry skin
  • Skin rashes

Apart from the health effects, a surge in the pool’s pH affects swimming gear. You’ll notice premature wear and tear of swimming suits and goggles.

Lowers Chlorine Efficiency

Chlorine becomes less effective when the pool’s pH levels are high. When chlorine interacts with water, it forms hypochlorous acid. This acid is responsible for inactivating all pathogens in water.

Hypochlorous acid functions best in acidic conditions. If your pool’s alkalinity is too high, hypochlorous acid will not kill all the microorganisms in your pool.

You have to find a median pH that is safe for swimming and doesn’t curtail the effectiveness of hypochlorous acid.

Causes Scaling

High alkalinity makes pool water hard. Hard water is susceptible to creating scale formations from calcium deposits. The build-up of scales may block or clog your pool’s pipes and filters and damage your salt cell in a saltwater pool.

Clogged filters and pipes affect water circulation and may significantly strain your pool equipment. Your pool might face issues like motor failures or even leaks. In the end, you incur considerable costs in replacing pool equipment.

Poor Water Quality

High pH levels affect the water quality in your pool. As mentioned above, chlorine is less effective in killing algae when the water is very alkaline.

Very high pH also affects the solubility of chemicals like calcium. You’ll notice cloudy water if such chemicals don’t dissolve.

I recommend testing your pool before and after adding chemicals. The key things to check are pH, total alkalinity, and acid demand.

How to Lower pH Level in Your Pool: Two Strategies

If you notice the pH levels are high, you should work immediately to restore the right balance. There are two chemicals you can use to lower PH levels in pools. The two products are:

  • Sodium bisulfate
  • Muriatic acid

The industry term for these products is pH reducers. Some brands refer to them as pH minus. When shopping, you must be familiar with both products because muriatic acid is more potent than sodium bisulfate.

Sodium Bisulfate

Sodium bisulfate is a dry acid that forms when sulfuric acid reacts with a base like sodium hydroxide or sodium chloride. Although reactions between acids and bases yield neutral products, sodium bisulfate is only partially neutralized. It has an acidic pH of about 1.

Sodium bisulfate has many names. You may also know it as dry acid, bisulfate of soda, sodium hydrosulfite, sodium hydrogen sulfate, sulfuric acid sodium salt, monosodium hydrogen sulfate, acid salt, or niter cake.

Is It Safe?

Sodium bisulfate is a safer product compared to muriatic acid. It comes as a fine powder, so be cautious when using it in windy conditions.

How to Lower pH Levels Using Sodium Bisulfate

When it comes to pool maintenance, dry acid primarily acts as an acidity regulator. You use it to curb runaway pH levels of your pool water.

Precautions

Avoid using sodium bisulfate during windy conditions. The wind can easily blow this fine powder back into your eyes, hands, or skin.

A few things you’ll need include:

  • A pool test kit
  • A plastic bucket. Do not use metallic containers
  • A stirring rod (wooden or plastic)
  • Safety equipment like gloves and glasses
  • A measuring cup (plastic)
  • Sodium bisulfate
  • A plastic scoop

Once you’re set, follow these steps.

Step 1: Test the PH

It’s always advisable to test your pool water before applying pH reducers. The ideal pH range should be between 7.2 to 7.6. If you find the pH is above 7.6, proceed and use sodium bisulfate.

Step 2: Decide the Quantity to Add

The quantity you should add depends on the pool size and the manufacturer’s instructions. It may also depend on how high your pool’s pH is.

I recommend only adding three-quarters of what the manufacturer suggested. You’re unlikely to add excess dry acid if you follow this rule.

Step 3: Add the Sodium Bisulfate

Once you measure the ideal amount, pour the powder into the pool near the return jets. Avoid adding sodium bisulfate near the skimmer.

Some manufacturers advise pre-dissolving sodium bisulfate in a bucket before adding it into the pool. If you decide to do so, ensure you add the dry powder to water and not the other way around. Pouring water onto the powder can cause chemical boiling which can be harmful.

Afterward, turn on the pool to evenly distribute the sodium bisulfate granules. If you don’t have a pool pump, you can use a paddle to circulate the water manually.

Step 4: Allow the Sodium Bisulfate to Dissolve

Dry acid doesn’t work instantly. It needs time to dissolve before it does its job.

Step 5: Re-test the Pool’s pH

After waiting for several hours (about six hours), re-test your pool’s pH. If the levels are still high, you need to repeat the entire process. This time, ensure you add the sodium bisulfate slowly.

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Muriatic Acid

Muriatic acid is an impure form of hydrochloric acid. It’s a caustic acid with a pH of about 1-2. Homeowners mostly use it to wash tiles, clean bricks, and clear drains.

As a pool owner, you can use this acid to offset high pool pH levels.

Is It Safe?

Muriatic is a very corrosive acid. It is capable of corroding anything, be it clothing or metal.

This acid is safe for home use, provided you take safety measures and follow the manufacturer’s instructions.

How to Lower pH Levels Using Muriatic Acid

If you suspect your pool’s pH is high, it might be time to add muriatic acid.

Precautions

Muriatic acid comes in liquid form. It can burn your skin at the slightest contact, and its fumes can affect your respiratory system. You should handle this acid using full protective gear.

We recommend the following things.

  • A chemical-resistant apron
  • Acid-resistant gloves
  • Chemical fume protective mask
  • Safety goggles
  • A plastic bucket
  • A stirrer (wooden or plastic)

Once you’re ready, follow this guide

Step 1: Test the Pool’s pH

Your pool’s pH range should be between 7.2-7.6. If it’s higher, consider lowering it using muriatic acid.

When testing the pH, you can use test strips, differential sensors, or process sensors.

Step 2: Wear Protective Gear

Before handling muriatic acid, you must wear protective clothing. We urge you to wear acid-resistant gloves, safety goggles, an acid mask, and a chemical-resistant apron. Make sure the apron covers your legs and arms.

Step 3: Measure and Dilute the Muriatic Acid

The ideal amount of acid to use is indicated in the manufacturer’s instructions. You may need to dilute muriatic acid before adding it to the pool. Diluting the acid makes it less dangerous if it splashes. Always add the acid to the water bucket and not water on the acid.

Step 4: Turn on the Pump

Turning the pump on or off is a matter of preference. Some claim that when the pump is on, it adds oxygen to the acid and amplifies the pH levels.

However, we recommend turning the pump on due to the strength of the acid. Muriatic acid might corrode the pool’s floor if left too long in one section.

Step 5: Add the Muriatic Acid

Walk around the pool while slowly pouring the acid. Concentrate more in the deep end of the pool. After you’re through, rinse off the bucket.

Step 6: Give It Some Time

It may take up to 30 minutes for the acid to disperse into the pool water. During this period, no one should enter the pool.

Step 7: Re-check the pH Levels

Re-test the water after 3-4 hours to make sure the pH levels are optimal. If they are off, add more muriatic acid until you achieve the ideal levels.

Safety Tips

It’s advisable to exercise caution when adding muriatic acid and sodium bisulfate to your pool. Always ensure you:

  • Wear protective gear
  • Don’t mix these products with chlorine. Such a combination produces toxic fumes
  • Add the acid into a bucket of water and not the other way round
  • Only use three-quarters of the recommended portions
  • Do not use the pool a few hours after adding pH reducers
  • Use plastic buckets

And that’s about it. Don’t be intimidated by either of these methods for lowering your pool water’s pH level. If you overshoot it, make sure to check out my article on how to raise the pH level in your pool.

A Few Tips to Keep Your pH Balanced

Your pool’s pH level is not permanent and will inevitably change over time. As a pool owner, you will need to adjust these levels often. But here are a few tips to keep the pH balanced and help minimize the frequency of needing to lower the levels.

Test your pool water frequently. PH levels can change very quickly based on many different factors. So consistently checking the levels is imperative.

Keep your pool clean and sanitized. A clean pool is less likely to have issues with chemical imbalances.

Shock your pool only when necessary. High amounts of chlorine can cause the alkaline levels to rise high. This is why you should only shock your pool when it is necessary.

Check your tap water. Not all water is created equal. Tap water in some areas has high mineral content and could have a higher pH level.

Frequently Asked Questions

Does baking soda lower pH in your pool?

Baking soda is an alkaline chemical and it is used to raise the pH level of your pool water. It is used to improve the clarity of your pool when you have a pool below 7.2 to 7.6 pH.

Can you lower pH in your pool naturally without adding more chemicals?

There are a couple of methods you can use to lower the pH in your pool naturally. The first is to heat the pool. Doing so will lower the pH levels thereby increasing the acidity of the water. The second option is to simply leave the water alone. The pH in your pool water should naturally decrease. Once the water gets below the recommended pH level of 7.2, change the water.

Is the process for lowering pH in your saltwater pool any different?

The process of lowering pH in a saltwater pool is essentially the same as with a chlorinated pool. There are no real differences in the process. You just need to test the water and add a pH decreaser like muriatic acid or sodium bisulfate.

Any more questions? Let me know.

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