For all pool owners, maintaining a balanced pH is essential for safe, comfortable swimming and keeping your pool water clear. However, if your pool water is starting to look cloudy, feel irritating, or doesn’t seem right, your pH levels could be too high.
In this guide, we’ll show you exactly how to lower pH in your pool using a series of simple, safe steps. From testing your water to choosing the right pool chemicals, you’ll learn to get everything back in the ideal range quickly.
Whether you’re tackling the issue yourself or looking for professional help from us, this is your go-to guide for restoring a healthy swimming environment.
Understanding Pool pH and Why It Gets Too High
Your pool’s pH level measures how acidic or alkaline the water is. A perfectly balanced pool sits between 7.2 and 7.6 on the pH scale. In other words, just slightly alkaline.
But when pH creeps too high, it can cause skin irritation, burning eyes, cloudy water, and reduce the effectiveness of your chlorine.
So, why does this happen? Some of the most common reasons include overuse of sodium bicarbonate, excess aeration (like waterfalls or spa jets), or adding certain chemicals incorrectly.
Even environmental factors like heavy rain or heat can push your pH up. Subsequently, knowing what causes high pH is the first step to keeping your swimming pool healthy and usable.
How to Lower pH in Pool: Step-by-Step Instructions
Lowering the pH in your swimming pool doesn’t need to be complicated. But it does require you to understand the right method to employ and exercise a bit of care.
Follow these step-by-step instructions to bring your pool water back into balance and keep your swimmers comfortable and safe.
Step 1: Test the Current pH Level
Take a water sample from the deepest part of your pool using a pH test strip or a liquid testing kit.
Ideally, you want to achieve a reading of above 7.6, as this indicates high pH. However, don’t forget to check your total alkalinity as well.
Step 2: Choose the Right Pool Acid
To safely lower pH levels, you’ll need an acid-based product, such as muriatic acid (also known as hydrochloric acid) or sodium bisulfate (dry acid).
Both of these are designed for most types of swimming pools and meet Australian standards. But typically, Muriatic acid is stronger and faster-acting, while sodium bisulfate is easier to handle.
Step 3: Calculate the Correct Amount
It is important to always follow the manufacturer’s dosing guide. As a general rule, around 200ml of pool acid is enough to lower the pH by 0.2 in a 50,000-litre pool.
We suggest starting small because you can always add more later. Using the correct amount is key to avoiding a sharp drop in pH or total alkalinity.
Step 4: Add the Acid Safely
Always wear protective clothing, including gloves and goggles, when trying to improve the pool’s pH levels. Additionally, please make sure you dilute acid in water (never the other way around) and pour it slowly into the pool near a return jet, with the pump running. Doing this will help to circulate the pool chemicals properly.
Step 5: Retest and Adjust
After 4 to 6 hours, test the water again. If the pH level is still too high, repeat the process using smaller doses until you reach the ideal range.
How pH Affects Swimming Pool Health and Safety
Aside from achieving good water clarity, one of the primary reasons you should keep the right pH level in your pool is that it directly impacts on people’s health, comfort, and pool maintenance.
When the pH is too high, chlorine becomes less effective, which allows bacteria and algae to thrive. It can also lead to skin irritation, itchy eyes, and scaling on your pool walls and equipment.
On the flip side, low pH can corrode surfaces and harm swimmers. Therefore, a properly balanced pH helps keep your water clean, protects your pool surface, and ensures that chemicals work as intended.
In short, good pH control means a safer, more enjoyable swimming environment.
Bonus Tip: Lowering pH Without Affecting Alkalinity Too Much
Unfortunately, lowering pH can often reduce your pool’s total alkalinity. However, there’s a clever way to limit that drop.
After you add the acid, try increasing the aeration in the pool by running spa jets, waterfalls, or fountains. Doing this should boost its pH slightly without greatly impacting its alkalinity levels.
That said, if the alkalinity level does fall too far, you can raise it gently with sodium bicarbonate. Just make sure you go slow and test in between to achieve the right balance.
How to Prevent High pH in the Future
If you want to keep your pool’s pH levels stable over time, you must get in the habit of performing smart and consistent pool maintenance.
A good starting point is to use a pH tester strip or digital kit to test your pool surface water regularly, at least once or twice a week. This helps you to identify changes early before they become a bigger issue. Just be careful when you add chemicals like sodium carbonate (baking soda) or soda ash. Too much can cause a spike in both pH and alkalinity.
After heavy rain, lots of swimmers, or a big chlorine top-up, it’s wise to retest and modify accordingly. Additionally, keeping your filter clean, monitoring the filter setting, and running the pump for long enough each day also helps distribute chemicals evenly and keeps the pool water clear.
Finally, using a pool cover can reduce carbon dioxide loss from UV rays, which is another common cause of rising pH. A little prevention goes a long way toward maintaining a balanced pH level.
FAQs
Can high pH levels cause itchy skin and eye irritation?
Yes. High pH levels can lead to itchy skin, burning eyes, and general discomfort for swimmers. It also reduces the effectiveness of chlorine, which makes it harder to keep your swimming pool sanitised.
What’s the difference between alkalinity and pH?
pH measures how acidic or alkaline your pool water is, while total alkalinity levels act as a buffer to help stabilise pH. When alkalinity and pH are both out of balance, it becomes more difficult to maintain safe, clear water.
How often should I test my pool water?
We recommend you test your swimming pool regularly, at least once or twice a week, especially after storms, heavy use, or when you have added chlorine or a small amount of other pool chemicals.
Is there a safe way to manage both pH and alkalinity?
Yes. The safest way is to adjust one level at a time and monitor the changes. Slow, steady changes are the most effective. Never overdo chemical additions running your filtration system longer and shock the pool if needed to stop algae before it starts growing.
