Every time you check the alkalinity, hardness, and chlorine levels in your pool, you should also be testing its pH. If your water is too acidic or too basic, it can have a damaging effect on both your pool and your own health. Once or twice a week, head out to your above-ground pool with a test kit and add chemicals as necessary. Learn more about the importance of keeping your pool fresh and balanced! Read on for Haven Spa Pool & Hearth’s brief guide on how to check your pool’s pH, and keep it handy every time you need a refresher.
Why Do I Need To Check It?
Dust off your chemistry knowledge from high school for a moment. The pH level of a substance lets you know how acidic or basic it is, on a scale from 0 to 14. Pure, distilled water sits at a perfect 7.0. Your pool’s pH level should be between 7.4 and 7.8; if it goes outside of this range, you’ll need to add chemicals to balance it out. But why?
When your pool water is too acidic, it irritates your skin and eyes. Your sinuses will dry out and your nasal passages will feel parched. Meanwhile, it’ll erode plaster and grout on the inside of your pool, and the extra acidity will corrode any metal components. If your pool water’s pH dips below 7.4, it makes the chlorine in your pool less effective and can lead to algae buildup, too.
What if your pool water is too basic? If its pH creeps above 7.8, it’ll also decrease the effectiveness of the chlorine and lead to cloudy, dirty water. Your skin will get dry and itchy, much like with acidic water, and it can cause undue wear and tear to goggles and bathing suits.
Testing the Water
You should test your pool’s water at least once a week. Haven Spa Pool & Hearth’s above-ground pools in Portland, Oregon are roomy enough for plenty of people; if you host parties or use the pool every day, test the water more often. Every time it rains, test your water afterward.
There are a couple of different methods for testing your pool’s pH. Simple test strips are affordable, quick, and easy to read. If you’re using a test strip, submerge it in well-circulated water close to the middle of your pool, dipping your arm in up to the elbow. Count to 30 before taking out the strip and laying it on a flat surface. The bottle your strips came in will have a color chart on the label, so you can easily match colors and read the pH within minutes.
Testing kits are the most accurate way to measure your pool’s pH, but they’re a little more finicky than test strips. You’ve got tubes and reagents to work with now. Make sure to rinse the comparator tube clean before filling it, and follow similar protocols as you would with a test strip. Dunk that tube into the middle of the pool, with your arm up to the elbow in the water. Fill the tube to the top line and get your reagent ready; phenol red is a common reagent for pH testing. Use an eyedropper to drip exactly five drops into that comparator tube full of pool water. Your test kit will have a color chart, much like a bottle of test strips, so you can compare the color of the water to the numbers on the chart.
It’s Too Low!
Is your pool water too acidic? If that pH number is below 7.4, you’ll need an alkali chemical like sodium carbonate (commonly called soda ash) or sodium bicarbonate (which we all know better as baking soda). Be careful about the alkalinity of the pool, though, as that’s a different level you need to test every week.
If your pool’s pH is low but its alkalinity is high, the water will be more resistant to a pH change. To decrease the alkalinity without lowering the pH too much, pour the recommended amount of acid to correct alkalinity into one spot at the deep end of the pool. Concentrating the chemicals in a single spot is a gentler way to lower alkalinity without having a disastrous effect on the pH. You can also aerate the pool and get some bubbles going. Aeration will get more carbon dioxide bubbles in the water, which form carbonic acid that gently raises the pH.
If the pH and alkalinity are both low, add your alkalinity increaser first. The pH may rise in tandem with the alkalinity. If it doesn’t, add a pH increaser like sodium carbonate.
It’s Too High!
If you’ve tested your pool water and the pH is more than 7.8, it’s too basic. You’ll need to lower that pH with an acidic compound. When you shop for chemicals, look for something called “pH decreaser” or simply “pH-minus.” They’re mostly muriatic acid and dry acid (sodium bisulfate).
You should be testing your pool’s alkalinity, calcium hardness, and chlorine levels when you test the pH. Check the pH against the alkalinity and choose chemicals as necessary. If your pool’s pH is high but its alkalinity is low, prioritize the latter. Using the same technique described above, pour the recommended amount of alkalinity increaser into a single spot at the deep end of the pool. This trick gently raises the alkalinity without raising the pH too much. Make sure you add this chemical before using a pH decreaser like muriatic acid.
If the pH and the alkalinity of your water are both too high, you only need the pH decreaser—generally sodium bisulfate or muriatic acid. It’ll lower the alkalinity along with the pH.
After you install your above-ground pool, take meticulous care of it by testing the water regularly. Your pool’s pH levels have a tangible effect on both the condition of your pool and your own well-being, so don’t slack off on it! Keep Haven Spa Pool & Hearth’s brief guide on how to check your pool’s pH on hand next time you go out there with your testing kit.