The biggest ever problem faced by the aquarist is maintaining a constant pH level. Many hobbyists fail to understand why a constant pH level is necessary in the aquarium and what factors influence the pH reading.

Why pH is important for your aquarium

For a good and healthy aquarium, maintaining a constant pH can greatly influence the water in your tank. For instance, if your pH drops below 6, the nitrification bacteria that keep your ammonia and nitrites (toxic compounds to fish) at 0 ppm, will begin to die off.

If you don’t maintain a constant pH level, then the ammonia level of your tank will fluctuate. The total ammonia is a combination of ammonium ions (NH4+) and ammonia (NH3). The pH of your water is a major factor in the relative concentrations of these two compounds. More ammonia (the more toxic of the two compounds) will be present in alkaline water while more ammonium ions (the less toxic of the two compounds) will be present in acidic water. After the cycle is completed, there should not be any ammonia in your tank anyways.

Which pH level will you maintain in your aquarium

When considering pH, you should know which pH you will maintain for your aquarium. For example, discus fish love to live in a high pH level, 7.0 maybe the optimal pH level. The same fish will likely thrive at a constant level anywhere between 6.6 and 7.4. and, for their breeding, you should keep 6-6.5 pH level. For a marine aquarium, you should keep a level that is higher than 7 pH level. In other words, a constant pH of 6.6 is better than a pH value which fluctuates between 6.6 and 7.0, even for a fish that prefers a 7.0 reading.

How to Test Your Tap Water’s pH

Many hobbyists test their tap water right away for pH. However, this is not a good indication of your pH. To properly measure your tap water’s pH, pour some tap water into a bucket and place an air stone in the bucket to agitate the surface. Then let this bucket of water sit out for 24 hours. After this, test the water for its pH. It is then a good idea to check it after 48 hours to see if there is any additional change. These values measured after 24-48 hours are an accurate measure of pH of your tap water.

In this time, carbon dioxide in the water causes the pH to drop. By exposing your tap water to the air and agitating the surface, you are causing a gas exchange at the surface of the water. This exchange reduces the amount of carbon dioxide in your water and causes the pH to rise. This pH will be the actual one you will measure in your tank.

If the fish you want to keep have very special pH requirements, like discus fish, and the required pH level is reasonably close to the pH level that your aquarium water is naturally buffered to, then I do not recommend you make any changes. On the other hand, if your fish have pH requirements which are far from the values in your tank, then you have to take some steps to adjust it to a more suitable level.

Check Your Test Kit

Many newbies in this hobby have this problem – the test kit they use does not give correct reading. This can be frustrating for a new fishkeeper who then thinks there is a pH problem, when actually there is not, and then does lots of things to stabilize the pH level and, ultimately, cause the fish to die. Therefore, if you are getting a reading that is either too low or too high for your taste, the first step is to investigate the test kit that you are using to see if it is accurate, or not.

Most test kits have its own life (usually 6 months). If your test kit is older than this, it may be providing inaccurate results If you are sure the kit is not out of date and that you followed the directions exactly then you can be confident that you are obtaining an accurate reading of the pH.

Ways to Raise Your pH

As stated above, it is generally a better idea to acclimate your fish to the pH of your water than to adjust your water to suit the pH preference of your fish. There are certain steps that can be done to raise the pH level in an aquarium.

● Water Changes – if you do not change the water of your aquarium, the pH in your aquarium will drop. The most effective method to raise it back up to the level of your tap water is to do regular water changes. If you notice that your aquarium has a fluctuating or deviating pH then do 30-40% partial water change of your aquarium.
Vacuuming all of the uneaten food and waste will also help to counter the tendency for the pH to drop over time.

● Rocks or driftwood – Add some rock or driftwood in your aquarium for raising the pH. Crushed coral is used as the substrate in many African cichlid tanks (African cichlids prefer a high pH of 7.0). Limestone and petrified coral will also do the trick. If you do not want to add these rocks, you can add a bag of crushed coral to your filter or hide some of these rocks behind the rocks you do want to showcase. For a discus aquarium, you cannot keep rocks whereas you can keep driftwood.

● Aeration – Increasing the oxygen concentration in your water will serve to drive down the carbon dioxide concentration. As discussed above, less carbon dioxide translates to a higher pH. Therefore, you can increase the aeration in the tank to raise the pH.

● Baking soda – Adding baking soda will also raise the pH, but if you add baking soda once an just forget it then its purpose is not served yet. So you have to add baking soda in your tank constantly. You also need to be careful not to add too much at one time and cause a severe spike as this could kill your fish. It is best to gradually adjust the pH if you decide it must be adjusted. The general rule is 1 teaspoon per 5 gallons. For example, I have a 63 gallon discus aquarium so I put 13 teaspoons. Dissolve the baking soda in some water before adding it to the tank.

● Chemicals – There are several commercial buffers currently available on the LFS. However, these are generally not recommended as they can lead to large spikes in your pH and usually only serve as a temporary fix. They will not in general, maintain the pH in your aquarium.