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One of the most important factors for a clean, sanitary pool is maintaining a healthy pH balance. This is a term you’ll come across often but for most people, the last time we had to think about the pH scale was in high school science class. So, let’s start with a quick refresher.

pH is actually an abbreviation for “potential Hydrogen” and represents the concentration of hydrogen ions in a water-based substance. In simple terms, your pool’s pH level shows the acidity or alkalinity of the water. Too high or too low and we start to invite problems and complications pretty quickly. More on that in a moment.

Your pool’s pH is represented on a scale from 0 to 14 where 0 is the most acidic, 7 is neutral and 14 is the most alkaline. To put this scale into perspective, here’s a helpful diagram from AustralianEnvironmentalEducation.com.au. This shows typical pH levels for products you’ll be familiar with.

pH scale diagram

Clearly, this is a broad scale with quite a jump between each point — just 2 points difference between lemon juice and battery acid! Already, we can start to see why keeping a close watch on these levels is important.

 

What is a normal pool pH level?

A normal, healthy pH level for a pool is from 7.4 to 7.6. There are so many factors that can influence this from rainwater to chemicals and even sweat so it’s important to keep a close eye on these readings.

It’s always safer and easier to make small adjustments often than to wait for aglae to start forming then dumping a bucket of chemicals in.

 

Why your pool’s pH level is so important

Depending on how far out of that 7.4 to 7.6 range you allow your pool water to stray, there’s a range of negatives you’ll start to see. Most commonly:

  • Irritated eyes and nasal passages
  • Dry, itchy skin
  • Cloudy pool water
  • An increased likelihood of bacteria and algae
  • Corrosion on any metal surface or objects (ladders, screws, light fixtures etc)
  • Corrosion inside your pool pump
  • Etching and deterioration of concrete, tiling, plaster and grout
  • Weakened, brittle vinyl in an above-ground pool
  • Staining of your pool surface is left this way for too long
  • Increased running and maintenance costs
  • Scale buildup
  • Clogged filters
  • A reduction in chlorine effectiveness
  • Cloudy water

This is quite the list of negative side effects and all it can take is a long period of heavy rainfall and a lack of maintenance for these to start creeping in.

The good news is, keeping your pool pH level in check is pretty simple. Let’s take a look at how to check these levels and what to do when you notice it straying outside of that healthy range.

 

How to test pool pH levels

Given how important your pool’s pH levels are, you’ll find a range of test kits and devices made for exactly this purpose. Below is an overview of the three most common, though instructions and specifics will vary by brand.

For clean and healthy water, test your pool’s pH levels weekly. This means you only ever need to make minor corrections to stay within that ideal range.

Note: Test kits and strips generally only measure down to a pH of 6.8. If that’s the reading you see, it’s possible you may actually have a level that’s even lower.

 

Electronic pH Meters

electronic ph meter

Image Source: The Water Shop

An electronic meter is the best option if you only want to check the pH levels in your pool. Using them is generally as simple as turning them on, inserting them into a sample of your pool water and stirring gently for a few seconds.

Unlike other testing options, an electronic meter gives you an exact number which takes all the guesswork out of it. Since we’re trying to stay within a range of just 0.2 on the scale, getting a number is very helpful.

The drawback is simply the upfront cost. You can expect to pay somewhere around $100, though prices can vary from sub-$100 to well over $1,000. Generally, you get what you pay for, up to a certain point.

The flipside to this is you don’t have to keep spending money on them. Once you’ve purchased an electronic pH meter, the only thing you ever have to replace is the battery.

 

Test Strips

pool test strips

Image Source: Aquachek

Test strips are another easy test to use and are much cheaper to buy — generally in the $20 – $100 range. Since each strip is single-use (you’ll often find 100 strips in a kit), you will have to keep repurchasing as you run out.

Another key advantage of these test strips is that they generally test for several factors at once, not just pH levels like the electronic meters above. Pictured is Aquachek’s 7 in 1 test strips which check for each of the following, all at once:

  • pH
  • Total Alkalinity
  • Water hardness
  • Total Chlorine
  • Bromine
  • Free Chlorine
  • Stabilizer

All you need to do is hold the test strip in your pool water for a few seconds, take it out and give it 10 – 15 seconds to develop. You’ll start to see the colors changing and can compare it to the chart provided.

Cheap, extensive and easy to use.

 

Pool Test Kit

pool test kit

Image Source: Clark Rubber

The third and most complicated option you’ll see is a test kit like the ones pictured. They’re also inexpensive with a similar price range of around $30 to $100+. Also like the test strips, they’re generally designed to test several factors at once.

Unlike the strips, though, you’re going to feel like you’re back in that high school science class, only without the bunsen burner.

You have two tubes to fill with your pool water, then various test solutions to add and compare against the color scales seen on the side. Each test requires its own steps, water sample and solution. It’s not rocket science by any means but when you compare it against dipping a test strip in the water and waiting 10 seconds. . .

Now that we know what pool pH levels are all about and how to test them, it’s time to start getting the balance back in check.

 

How to fix a pool with a low pH level

At your local pool shop you’ll find a great range of products made specifically for increasing your pool’s pH level. They go by various names and advertise a range of added benefits but ultimately, they’re a sodium carbonate (aka soda ash) base with some proprietary additives. Since soda ash is an alkaline substance, it quickly increases your pH level.

  1. Turn your pump on
  2. Check your current pH level so you can make an accurate adjustment
  3. Determine the amount of soda ash you need to add — check the packaging for this ratio
  4. Follow the manufacturer’s instructions on how to add it safely
    Some require you to mix it with water first while others are just added directly to your pool (slowly!)
  5. Check again after ~12 hours to confirm the pH levels are back within a normal range

Note: These chemicals can be very dangerous. Follow all manufacturer instructions carefully, avoid using them in windy conditions and get as close to the pool surface as possible before adding them to avoid splashing. Gloves and goggles or glasses are always recommended, avoid inhaling the fumes.

 

How to fix a high pH level in your pool

Unsurprisingly, there are also products made specifically to lower your pH level as well. The two you’ll generally see are:

  • Hydrochloric Acid (muriatic acid)
  • Sodium Bisulfate (pH decreaser)

Although hydrochloric and muriatic acid aren’t technically the same thing, we tend to refer to them interchangeably since they’re functionally equal. Hydrochloric acid is just more potent.

That means you can follow the same steps below for either of these chemicals (and sodium bisulfate), just pay close attention to manufacturer guidelines as the ratios will not be the same for all three.

  1. Turn your pump on
  2. Check your current pH level so you can make an accurate adjustment
  3. Determine the amount of product you need to add (check the packaging for this ratio)
  4. Follow the manufacturer’s instructions to add it to your pool — typically diluting it in a 10:1 ratio to avoid a highly acidic backsplash.
  5. Pour it into the deep end of your pool, close to the jets for fast circulation
  6. Check again after ~12 hours to confirm the pH levels are back within a normal range

Note: These chemicals can be very dangerous. Follow all manufacturer instructions carefully, avoid using them in windy conditions and get as close to the pool surface as possible before adding them to avoid splashing. Gloves and goggles or glasses are always recommended, avoid inhaling the fumes.

 

The best way to maintain a healthy pool pH level year round

By far the best way to keep your pool in top shape all year is to keep on top of it. Weekly checks of your pH level are a great start. You also want to make sure you’re keeping surfaces clean, and your filter is running correctly.

By making these small, incremental changes, you can avoid any major complications like having to replace your pump or perform major, expensive maintenance.

For more information, take a look at our swimming pool maintenance guide.

Happy swimming!