How to Lower The pH Level in Your Pool (The Easy Way)

A high pH level in a swimming pool is bad and leads to various problems. But how can you lower the pH level in whirlpools and swimming pools?

To lower the pH level in the pool water, the total alkalinity must be first optimized to 300 ppm. Then, the pH level is lowered with liquid hydrochloric acid. You need 1 liter of pH minus (24%) to reduce the pH level in a 50 m³ pool by 0.5.

As a pool owner, it isn’t easy to prevent the pH level from rising. In this post, I will explain what you need and how to lower the pH level.

Lower the pH level in your pool

The correction of the pH levels ​​downwards is important for the water balance.

As a pool owner, you are more likely to have the problem of a high pH level.

But what to do when the pH level is too high, and what is the most effective way to lower the pH level in a swimming pool or whirlpool?

I have written detailed instructions on lowering the pool pH level with a pH minus.

Tip: Before you start measuring and lowering the pool pH level, you must first test the alkalinity in your pool and, if necessary, optimize it – you can find more about this in the linked article on my blog.

1. Measure the current pH level in the pool water

Preferably, use an electronic measuring device to test your pool water – under the link, you can find my complete blog article about suitable measuring methods.

I recommend the electronic tester, especially when the pH level in the swimming pool is exposed to strong fluctuations.

Electronic meters are much more accurate than test strips or other colorimetric methods of measuring pH levels.

The correct dosage to lower the pH level in your pool can only succeed if the data is precise. Source.

Tip: Do not measure the pH level of pool water immediately after chlorination. In this case, wait at least 12 hours.

2. Calculate the pool volume and water content

In addition to the exact pH level, calculating the pool volume is crucial for the correct dosage.

Use the following formulas to determine the water content:

  • Rectangular basin: length x width x average depth
  • Round pools: Radius² x 3.14 x depth (r² * π * h)

The volume of water in oval pools or free forms is difficult to determine precisely. In this case, you have to estimate the volume of water roughly.

Tip: When the water has been delivered, you can orientate yourself using the water volume when your pool was first filled.

3. Put on protective equipment

The pH reducer is acid, which irritates the skin, eyes, and mucous membranes.

That is why you should wear suitable protective equipment before dosing the pH-Minus. This includes rubber gloves and protective goggles.

I also recommend wearing old clothes as the splashes can damage the clothes.

Tip: If you don’t currently have proper protective goggles, then at least wear sunglasses, although suitable protective goggles are the better choice.

4. Dose the pH minus to lower the pH level

In the next step, the pH minus is dosed in the pool based on the data obtained – provided that the total alkalinity in your swimming pool is in the range between 200 and 400 ppm.

The exact dosage is crucial so that you can lower the pool pH level.

If too much acid is poured into the pool, the pH will drop well below the optimum.

We remember: In our pool, we aim for a pH level between 7.2 to 7.6. Anything below or above this level is wrong.

And how much pH minus has to be poured into your pool to correct the pH level down?

In a 50 m³ pool, depending on the concentration of the agent, you need:

  • 24% hydrochloric acid: 1 liter of pH minus to lower the pH level by 0.5.
  • 20% hydrochloric acid: 1 liter of pH minus to lower the pH level by 0.42.

Based on this dosing information, you know that you should always have at least 5 liters of pH minus in stock.

You will find further information on the dosage of the pH reducer on the product packaging – always pay attention to the manufacturer’s instructions and ideally use a measuring cup.

Then pour the pH minus into the return flow of the pool pump. This avoids splashes, and the pool chemicals are better distributed in your pool.

If you want to use a pH-Minus granulate, then the granulate must first be dissolved in the water bucket. The mixing ratio should be 10:1.

To lower the pH level by 0.1, you need 100 g of pH-Minus granules per 10 m³ of pool water.

There are also concentration differences with pH-Minus granules, and you should read the manufacturer’s dosage instructions beforehand.

Tip: Cheap pH reducers on eBay usually have a weak concentration. Buy good quality pH reducers for your pool maintenance.

5. Run the pool pump

After using a pH reducer in the pool, the pool pump should initially run for 30 minutes.

This ensures an optimal distribution of the pH minus and a better effect in the pool water.

How long do you have to wait until the pH minus takes effect?

The pH minus has an immediate effect.

There are no fixed times that say when you can swim again in your pool. That always depends on the concentration of the agent, the pool size, and the filter performance.

Many pool owners jump back into the pool immediately after using it.

My recommendation: Test the pH level, and only when the level is optimal between 7.2 to 7.6 you are allowed to swim in your pool again. Otherwise, the pool water will irritate your eyes.

6. Repeat the process

It takes time to lower the swimming pool’s pH level and bring it back under control.

If you have used too much of the pH reducer and the parameter has dropped below 7.2, use a pH plus. With the pH-Plus, you can counteract this and achieve the ideal level between 7.2 to 7.6.

That’s why every pool accessory set includes a pH plus in addition to the pH reducer.

In the next 4 to 6 weeks, you should measure and optimize the pH level 1 to 2 times a week – balance with the pH-lowering chemical and the pH-plus.

After this time, the pH level in your pool will normalize.

Repeat the processes described and check the water parameters ​​regularly. If the pH fluctuates significantly, check the alkalinity with an e-tester.

Tip: If the pH level falls far below the ideal level, read my instructions on raising the pool’s pH level.

Why does the pH rise in the pool?

As a pool owner, you will more often have the problem that the pH level rises excessively.

Several scenarios can cause a high pH level in your pool:

  • Air supply: A running filter system or countercurrent system starts a degassing process and increases the pH level.
  • Water circulation: If the water is circulated – set in motion – the pH level increases slowly.
  • Temperature: The pH level rises on warm summer days.
  • Organic contaminants: Too much organic contamination in pool water increases the pH level.

As a pool owner, it is difficult to prevent the pH level in the water from rising – this is natural.

But it is your job to check the pH level and, if necessary, to lower it so that there are no further problems in your pool.

The video briefly explains how to do this, but it’s best to follow my written instructions earlier in the article.

In the next chapter, you will find out which problems still occur due to a high pH level in your pool.

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

If the pH level in your pool water is below the optimum of 7.2 – 7.6, then you need to act quickly.

Even minor deviations lead to numerous problems with the water quality.

pH level Water Symptoms
over 7,6 basic Cloudy and milky pool water, the disinfecting effect of chlorine decreases
above 8,0 basic Lime on the walls and in the filter sand

The acidic water will lead to rust formation in your pool in the long run and can damage the expensive pool equipment.

Milky pool water is also a common problem if the pH level in your pool is too high. This is because the joints are torn out, and the lime content in the water increases.

So don’t wait to optimize the water if the pH level in your pool is too high.

The first step is to test the parameters in the pool water precisely.

I explained in detail above in the text how you can effectively lower the pool pH level.

Frequent questions about a high pH level in the pool water

Here, readers can find more interesting questions regarding lowering the pH in your pool or hot tub.

Can you lower the pool pH with home remedies?

Acids are used to lower the pool pH level.

According to this, home remedies such as citric acid can lower the pH, but how much do you need?

In addition, home remedies such as vitamin C in the pool are a nutritional basis for algae and bacteria that lead to clouding of the water – you can find more information in my blog under the link.

I, therefore, would not recommend home remedies to lower the pH level in your swimming pool or hot tub.

Can you swim in the pool if the pH is too high?

Basic (alkaline) water is not dangerous for humans.

Some scientists claim that the alkaline water disturbs digestion – if you swallow too much of the pool water.

However, this has not been scientifically proven.

In theory, you can still swim in a pool with a high pH level.

But how long does it work?

It becomes cloudy after a short time due to a high pH level, and I assume that you do not want to swim in a dirty pool.

Do not waste time!

First, lower the pH level in the water and then enjoy the fun in your pool.

Should the pool pH level be regulated automatically?

If you want to save yourself a lot of stress with water treatment in the pool, you should use an automatic pH metering system.

The dosing system can measure and adjust the pH level in your pool – so the pH scale always stays in the ideal pH range of 7.2 – 7.6.

However, these devices are not cheap. Nevertheless, an investment in a sensible pool metering system can be a smart decision in the long term.

When using such dosing systems, ensure that they are set correctly beforehand. Otherwise, the pH level will be too high.

Do you have any further questions about the pool pH level? Contact me at @contactswimfool on Twitter, Facebook, Pinterest – I’ll help you personally.

Have fun optimizing the pH.

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Hi. I'm Max Berg. I've been in the pool industry since 2015 and have always felt drawn to water. I'm the author behind swimfool.com, where I share my years of experience in pool maintenance and give helpful tips on keeping a swimming pool or hot tub clean. My tips reduce the costs of water treatment and protect the environment.

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