The pH level determines the level of acidity or alkalinity of a liquid. If you need to adjust the pH of your water, whether it's for a science experiment, gardening, drinking water, aquarium water, or so on, start by measuring the pH level. To increase or decrease the acidity of the water, add an alkaline substance such as baking soda. Meanwhile, the acidity of the water can be increased by adding an acidic substance such as lemon water.
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Method 1 of 3: Adjusting pH Levels for Fish, Plants, Pond Water, and Drinking Water
Step 1. Add peat to the aquarium tank to adjust the pH level
Fish are very sensitive to the pH level of the water and can die if it is too acidic or alkaline. Most fish species survive in relatively neutral water, with a pH close to 7. If the water becomes too alkaline, add peat to lower the pH. If the water is too acidic, add 5 ml of baking soda per 20 liters of water to increase the pH level.
- Find out the pH levels required for the type of fish you have by searching the internet or asking a pet fish shop. For example, if you keep koi fish, the pH level is between 7.5 -8. 2.
- You can buy peat at a pet fish store. Put a handful of peat in a gauze bag, and put it in the aquarium tank filter. Peat will reduce the acidity of the water over time.
- Rapid changes in pH levels can harm fish. Remove the fish from the tank before adjusting the pH level.
- Test the pH level in the fish tank before and after adjustment. In addition, do a test before and after adjusting the pH level of the pool water or drinking water, which is also discussed in this article.
Step 2. Change the pH level of tap water for plants or gardens
Most tap water can only survive on slightly acidic water, with a pH between 5.5 and 6.5. If you measure tap water and find it too alkaline or acidic, it is necessary to adjust the pH before watering the plants. You can add lime or wood ash to 4 liters of water to raise the pH level. If you want to lower the pH, add phosphoric acid or tablets designed to lower the pH of the water.
- If you don't know the ideal pH for a particular plant, look online or at your local nursery. Some plants are sensitive to pH levels and need water at the exact pH level. For example, onions thrive when given alkaline water with a pH level of 6.5-7.0.
- Check with your local nursery for the exact amount of pH-altering agent you need to mix. You can also buy lime, wood, ash, and phosphoric acid or other pH-lowering agents at nursery centers.
- If you repeatedly water your plants with water with a pH outside of 5.5–6.5, they will simply wilt and die.
Step 3. Adjust the pH level of the pool
Swimming pools should always be kept at a slightly alkaline pH level, between 7.2 and 7.8. This pH level tends to rise on its own so you should lower it regularly. Swimming pool manufacturers produce chemicals for this purpose. The two most commonly used substances are sodium bisulfate and hydrochloric/muriatic acid. These two substances must be mixed directly into the pool water.
- For more detailed guidance on raising or lowering swimming pool pH levels, consult the pool manufacturer's instructions.
- You can buy sodium bisulfate (also known as “dry acid”) or hydrochloric acid at a pool supply store.
Step 4. Treat drinking water if it is acidic or alkaline
Drinking water must have a normal level, with a pH of exactly (or close to) 7. If the test results show that the level of drinking water is acidic or alkaline, adjust it so that the pH is neutral. If the drinking water is acidic (low pH), add drops or pH tablets to neutralize the acid. Conversely, if the drinking water is alkaline (high pH), add a few drops of lemon water, which is naturally acidic.
- If you want the pH level to be permanently adjusted, install a water filtration system. If the water is alkaline, install a neutralizing filter or a soda ash/sodium hydroxide injection system.
- If the water is acidic, hire a professional to install an acid injection system into your home's water supply.
Method 2 of 3: Experimenting Water pH Levels at Home
Step 1. Add 5 ml of baking soda to a 230 gram glass of water
Baking soda is alkaline, with a pH level of 9. Add 5 ml of baking soda to a glass of water and mix with a spoon or other stirrer. Keep stirring until all the baking soda is completely dissolved. Then, measure the pH level of the water again using a lime strip.
If you start with neutral water (pH 7), the pH will rise to 8
Step 2. Add 1 teaspoon (5 ml) of lemon juice to a glass of water
Mix the two liquids with a spoon. Wait a few seconds, and watch how the pH of the water has changed.
Since lemon juice is acidic, with a pH value of 2, the pH level of the water in the glass will decrease to 6 or 5
Step 3. Experiment with different bases and other acids
Many common and dissolved liquids are present in the home and change the pH level of the water. Dissolve or mix a little substance at a time in a glass of clean water, then test using a litmus strip. If you are doing a science experiment, create a material to record the pH level of water mixed with various ingredients, each in a separate glass of water. Try adding:
- Coca-Cola.
- Red wine.
- Milk.
- Liquid soap or shampoo.
Method 3 of 3: Measuring the pH of the Water with a Test Strip
Step 1. Purchase a water pH test strip
A pH test strip, also known as a lime strip, is a small sheet of paper 5 cm long and 1.5 cm wide. This paper is coated with a chemical solution that changes color when exposed to the same substance or base. These pH test strips can be purchased at pharmacies or laboratory supply stores.
You can also buy pH strips at major online retail stores, or pet stores
Step 2. Dip 1 pH strip into the water sample for 10 seconds
Add 2.5 cm of pH strip to the water. Dip both sides; the entire strip is pH sensitive. Be sure to hold one end of the strip securely so it doesn't come loose when testing the acidity or alkalinity of the water.
- For example, put drinking water in a glass if you want to try testing the pH level of drinking water.
- If you want to try adjusting the pH of your fish tank's water, dip a pH test strip into the water from the top of the tank to test it.
- You can also use a dropper to drop 1-2 drops of the tested water onto the lime paper.
Step 3. Notice the change in the color of the lime paper
After the pH strip has been exposed to water for 10 seconds, watch the color change. The color of the strip will indicate the acidity or alkalinity of the water.
If the stripe doesn't change color right away, wait a few seconds
Step 4. Compare the pH strip with the pH color indicator
The pH test kit should have a color chart. This chart shows the colors of litmus paper when exposed to acids or bases. Match the color of the pH strip to the color of the chart, and you will know the pH level of the water.
In general, if the litmus stripe is red, it means the water is very acidic. If the color is yellow, the water is moderately acidic, green means moderately alkaline, and purple means very alkaline
Step 5. Measure the pH level using a digital reader for more accurate results
Litmus strips are fairly quick and effective at measuring pH levels, but there are more accurate methods available. A digital reader (usually called a “pH meter”) is a much more accurate device, being able to determine pH levels down to 2 decimal places. The trick, dip the tip of the pH meter into water until the screen displays the results.
- pH meters are commonly used in science laboratories and can be purchased or rented at laboratory supply stores.
- The pH meter needs to be recalibrated between each use. Follow the guidelines listed with the pH meter for best results.
