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Plus, learn what pH means and what you’re actually measuring
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If you’re interested in testing the alkalinity or acidity of a liquid, you can use pH strips to help you determine the pH level. All you have to do is dip the strip into the liquid, wait for it to change colors, and compare the change to a provided color chart. In this article, we’ll explain exactly how to test and read your results , plus show you some common household substances you can test (and how to adjust the pH) with tips from retired science professor Chris Hasegawa, PhD and aquarium specialist Marshall Stephens.

Reading pH Test Strip Results

Dip one end of a test strip into a substance for a few seconds. Remove the strip and let it react for a few seconds (check the instructions for details). Hold the strip against the provided color chart. Match the strip to the closest matching shade to determine the pH.

Section 1 of 3:

Using the pH Strips

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  1. The pH scale covers a range of 14 numbers, where 7 is neutral. Lower numbers are more acidic, while higher numbers are more alkaline (basic). A basic universal pH testing strip covers this entire range and is great for testing drinking water, aquariums, pools, and even soil. [1]
    • Some specialty strips test within a narrower range of pH. For example, pH strips for urine and saliva usually test for pH levels between 4.5 and 9.0. Make sure you’ve got the right range for your project.
    • pH strips are available online or at many pharmacies, drugstores, and big box stores.
  2. You don’t need to submerge the whole strip in the test substance. Hold the strip at one end and dip the other end in the liquid, then remove it after 2-3 seconds. [2]
    • Read the instructions that came with your pH strips for the recommended amount of time to leave your strip in the substance. Some strips may need up to 20 seconds. [3]
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  3. Depending on your specific product, you may have to wait a few seconds for the paper to finish reacting (read the instructions that came with the strips for exact details). Then, finding the pH level is easy: “You’re just comparing the colors to the colors on the box,” according to Dr. Hasegawa. [4] When you find the number associated with the color on the strip, you’ll have your pH reading! [5]
    • Your pH strips should come with a pH color chart (sometimes located on the box or packaging). Look for a universal chart online if you don't have one. Even if you can't match your color exactly, you should get a close approximation of the pH level.
    • For the best results, compare colors in a well-lit area.
    • Acids are generally represented by warm colors, such as red and orange, while alkalines are associated with cooler colors, like blue and green.
    • Dr. Hasegawa adds, “If you’re using simple litmus paper, the strips will turn either pink or blue.” [6] Litmus paper strips are a less exact way to determine whether something is generally basic (blue) or acidic (pink/red).
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Section 2 of 3:

Common Substances to pH Test

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  1. Pure water is neutral, meaning it should have a pH balance of 7. [7] Most drinking water falls in the range of 6.0-8.5. [8] Test your drinking water to see if it falls within this range. If it isn't, there may be a contaminant in your water supply.
  2. A swimming pool should stay at a pH balance of between 7.0 and 8.0. [12] Acidic swimming water can irritate swimmers and lead to corrosion of pool equipment, while basic or alkaline water can reduce the effectiveness of chlorine and lead to scaling on surfaces. [13]
    • To raise the pH: Add soda ash or baking soda to the water. [14]
    • To lower the pH: Add sodium bisulfate or muriatic acid to the pool. [15]
    • Follow your specific pH product’s dosing and safety instructions for the best results.
  3. The pH balance in your aquarium is critical to keeping your fish healthy. However, different species of fish thrive in different pH levels, depending on where they come from naturally. Research the best pH range for your fish and test your water to make sure it falls within that range. Most aquarium fish can tolerate pH levels between 6.5 and 8. [16]
    • To raise the pH: According to Stephens, “You can use coral-based rocks or a coral substrate that naturally gives off a high pH. Or, use pH increasers. Generally, the powdered forms are best because they have minerals in them that keep the pH high. Steer away from liquid pH that doesn’t have minerals in it.” [17]
    • To lower the pH: Add driftwood or peat moss to the tank, or install a reverse osmosis (RO) water filtration unit or carbon dioxide reactor (follow all product instructions carefully to protect your fish). [18]
  4. The average pH of saliva is around 6.7, but a normal range is anywhere from 6.2 to 7.6. [19] If you measure your saliva and the pH is too low or high, you may be at risk of dental erosion (enamel loss, tooth decay, and/or cavities). [20]
    • Make sure you don’t eat or drink anything for about 30 minutes prior to testing your saliva, as this can throw off the reading.
    • To maintain healthy saliva pH: Swish pH-balanced water in your mouth after eating or drinking anything other than water to raise your pH back to normal levels (it typically drops after eating or drinking something). Or, chew sugar-free gum with xylitol to produce more saliva and naturally raise your oral pH. [21]
    • If your saliva pH is consistently too high or too low, consult a medical professional for long-term solutions.
  5. 5
    Check the pH of your urine to monitor underlying health issues. A normal pH range for urine is between 4.6 to 8.0. A high pH may be due to issues with your kidneys, stomach, or a Urinary tract infection (UTI), while a low pH can be caused by diabetes, diarrhea, malnutrition, or other conditions that impact the body’s ability to remove acids. [22]
    • How to maintain healthy urine pH: In the short term, eat a diet full of fruits, vegetables, and/or non-cheese dairy products to increase pH, or fish, meat products, and/or cheese to lower pH. [23] For long-term solutions (and to diagnose any underlying issues), see your healthcare provider.
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Section 3 of 3:

What is pH?

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  1. The pH (potential of hydrogen) of a substance determines how acidic or alkaline it is. A pH test strip measures the concentration of hydrogen ions (H+) in a substance—the more ions there are, the more acidic the substance is (and the lower its pH is). [24] Here’s a breakdown of some common substances and their pH levels for reference. [25] Note that the pH scale is logarithmic; going up or down one value on the scale means the pH is 10 times stronger or weaker. [26]
    • 0 (extremely acidic): Battery acid
    • 1: Stomach acid
    • 2: Lemon juice and vinegar
    • 3: Orange juice
    • 4: Tomato juice, beer
    • 5: Black coffee, Peptobismol
    • 6: Urine, saliva, milk
    • 7 (neutral): Pure water, blood
    • 8: Eggs, baking soda, seawater
    • 9: Toothpaste and hand soap
    • 10: Mild detergent, milk of magnesia
    • 11: Household cleaners, ammonia
    • 12: Hair straighteners
    • 13: Bleach, oven cleaner
    • 14 (extremely alkaline): Liquid drain cleaner

Expert Q&A

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  • Question
    How do you read a pH indicator strip?
    Chris Hasegawa, PhD
    Retired Science Professor & Dean
    Dr. Chris Hasegawa was a Science Professor and the Dean at California State University Monterey Bay. Dr. Hasegawa specializes in teaching complex scientific concepts to students. He holds a BS in Biochemistry, a Master’s in Education, and his teaching credential from The University of California, Davis. He earned his PhD in Curriculum and Instruction from The University of Oregon. Before becoming a professor, Dr. Hasegawa conducted biochemical research in Neuropharmacology at the National Institute of Health. He also taught physical and life sciences and served as a teacher and administrator at public schools in California, Oregon, and Arizona.
    Retired Science Professor & Dean
    Expert Answer
    Take a good look at the color of your strip. Then, compare it to the color guide on the box that your strip came in.
  • Question
    My pH test is 5, how can I improve my test result to 7?
    KnowledgeIsForever
    Community Answer
    A pH of 5 indicates your solution is acid and a pH of 7 means neutral. Therefore, you have to add a base. In the lab, you can do it with a sodium hydroxide solution - but be careful and always check your new pH with som more stripes or a pH meter! Keep in mind that this method is only appropriate for the lab and not aquariums (or any other systems).
  • Question
    What is the normal pH of the stomach?
    Han
    Community Answer
    Gastric acid has a normal pH between 1.5 and 3.5; about as acidic as undiluted lemon juice.
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      About This Article

      Article Summary X

      First, dip your pH strip into the liquid you want to test, like your pool water or garden soil. Read the instructions on the box to see how long to leave the strip in the substance. Once the right amount of time has passed, remove the strip and look at it to see what color it has turned. Compare it to the colors on the pH chart that came with the strips to determine the pH level of your substance. For ideas on what to test, keep reading!

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