You have your pool, your testing kit, and your chemicals — you’re a confident pool owner and you’re dying for an afternoon swim. Before you dive in, however, it’s a good idea for you to get acquainted with a little thing called pH.
You’ve heard of it before but why does it matter when it comes to your pool? Low pH can take your pool and turn it into a post-apocalyptic swamp before your first summer swim season has ended. Do I have your attention now? Awesome. Let’s dive in.
The Magic of pH
It’s hard to believe that the invisible force of pH has such a profound impact on the water in your pool (and everything it touches) but how does it work?
The abbreviation “pH” stands for “potential hydrogen” and is a measurement of how acidic or basic a substance is, or more specifically, how it interacts with hydrogen ions.
The scale has a range of -5 to 14 where 7 is neutral and is the pH of pure water. On the low end, we have the acids that contain very little oxygen. The higher numbers above 7 are the bases that are rich in oxygen.
The amount of oxygen is what determines how something reacts with hydrogen: whether it attracts or repels hydrogen ions. Exciting stuff, right? But why should you care? (Unless you’re secretly a chemistry enthusiast.)
Why pH Matters When It Comes To Your Pool
Not only does low pH affect your pool but it affects the comfort of swimmers too. It’s an important issue to solve as quickly as possible to avoid costly damage to your pool equipment and distressing experiences for swimmers.
Bad News For Your Pool
Low pH can have some seriously damaging effects on your pool equipment and your pool itself. When the pH of your pool water drops too low it becomes more acidic than it should be and can actually start to corrode metals, plaster, grout, and even tiles.
You may notice etching on the bottom or sides of your plaster pool and deterioration of your metal pool stuff, such as ladders, railings, or fixtures. But that’s not the worst of it. Acidic water circulates through your pump/filtration system and can do significant damage there that you won’t see… until it’s too late.
You may think you’re safe with a vinyl-lined pool but, I hate to break it to you, the acidic water caused by low pH will make that vinyl liner so brittle that it may tear or crack at the slightest touch.
As the acidic water eats away at the metals, plaster, grout, and other materials in your pool, those trace minerals float around until the water reaches its saturation point. When that happens, all of it falls out of solution, leaving nasty stains on surfaces and making your water cloudy and discolored.
And if all that wasn’t bad enough, here’s the kicker: low pH basically annihilates your chlorine’s effectiveness at sanitizing your pool. If the pH of your pool is out of balance, your chlorine won’t do a thing. You can dump in all the chlorine you can find and the pH of the water will render it useless.
I probably don’t have to tell you about the can of worms that will open. Improperly sanitized pool water is just an open invitation to algae, bacteria, and other organisms that will pop in and make themselves right at home. Before you know it, low pH won’t be the only problem you have with your water chemistry.
Bad News For Swimmers
Swimming in a pool of acid literally sounds like the beginning of a script for a terrible horror movie.
Of course acidic pool water is bad news for swimmers! It burns your eyes, your skin, and irritates your mucous membranes in your nose. It strips the natural oils from your body and makes everything dry and itchy.
It’s uncomfortable, it burns, and it does not make for a fun day in the sun.
What Causes Low pH?
The pH of your pool water is a finicky thing and there are a whole host of little things that will throw it off.
- Organic debris: Leaves, grass, bugs, etc.
- Local water: The pH of the water you use to fill up your pool may be more on the acidic side and may contribute to a low pH.
- Rainwater or recent storm: Rainwater is naturally acidic and an especially big storm can cause serious drops in your pH, sometimes overnight.
- Swimmer’s residue: Body oils, lotions, saliva, urine, deodorants, and any other products that swimmers might transfer into the water can significantly affect pH balance.
- Pool chemicals: You may have recently shocked your pool or added a sanitizer (chlorine and bromine are both very acidic), which can all contribute to a lowered pH.
With so many factors contributing to a lower pH (and a more acidic pool), it’s no wonder that you’re struggling to keep your pH in the right place. Luckily, there’s only one thing you need to raise the pH of your pool water in no time.
How to Raise the pH of Your Pool
The industry standard has historically been to use sodium bicarbonate (or baking soda) to raise the pH in your pool. And why not, right? It’s a cheap, easy to come-by product that has tons of uses around the house. The only problem is that baking soda is not as efficient and has a serious effect on alkalinity.
As a savvy pool owner, I’m sure you’re aware of the codependent relationship that pH and alkalinity in pool water have. When one goes up, the other does too — and vise-versa. Baking soda ruins this relationship, affecting alkalinity more than the pH and will actually cause a yo-yo effect with your pool water chemistry.
Don’t get me wrong, sodium bicarbonate will do the job… but it’s not the best tool for the job and it will take a lot more of the stuff than say, an alternative. Luckily, there is a better option out there: sodium carbonate (or soda ash).
With the same alkalizing potential as baking soda but without the dreaded “yo-yo effect,” soda ash is a great choice to raise the pH of your pool easily and in just five steps.
Step #1 – Test your pool water
Grab your pool test kit and do your thing. Make sure to pay special attention to your pH. We’re looking for 7.2-7.6 here, with 7.4 being the sweet spot. If your levels are lower than 7.2, read on.
Step #2 – Determine your pool’s capacity
You probably already know the volume of water your pool can hold, but just in case you’re adding soda ash to a friend’s pool out of the kindness of your heart… here are the quick calculations you’ll need to do.
- For a rectangular or square pool: Length x Width x Depth x 7.5 (Average the depths of your pool if there’s a deep end and shallow end)
- For a round pool: Diameter x Diameter x Depth x 5.9
Step #3 – Measure the amount of soda ash you need
Make sure to follow the manufacturer’s instructions here but the general rule of thumb is that 6 oz. of soda ash will raise the pH of a 10,000-gallon pool by 0.2 points.
So to get from a pH of 6.8 to the minimum (safe pH) of 7.2 for a 20,000-gallon pool, you would need to add 24 oz. of soda ash. Do the math for your own pool to get the exact amount you need.
Step #4 – Add the soda ash to your pool
It’s a good idea to dilute the soda ash in a bucket of water before adding it to your pool. Be sure to be safe and wear gloves and goggles when working with chemicals.
If the instructions recommend that you add the soda ash directly to the pool without dilution, add it very slowly then grab your pole brush and sweep it around to avoid damaging the floor of your pool.
Always only add 75% of what you planned to add to the pool, turn on your pump for an hour, and then retest. This is a great way to save you having to lower the pH again and playing that annoying up-and-down game.
Step #5 – Retest your pool water
Once you’ve added the soda ash and circulated the water for an hour, it’s time to retest.
If you used the 75% method and your pH is still too low, go ahead and add that last 25% and repeat the process until you get your pH back up to where it needs to be.
Balance is Beautiful (And Good For Your Budget)
By now it’s probably obvious how important it is to keep your pH in check — not only for your pool itself but for the health and safety of your family and friends… not to mention your wallet. Low pH can have devastating effects on your normally well-maintained pool, causing damage and costing you a fortune.
However, with frequent testing, some soda ash, and a little math — you can keep your pool sparkling, clean, and perfectly balanced for every swim season.