How to Naturally Lower the PH for an Aquarium

There's nothing worse than coming home and finding that the fish in your carefully maintained fish tank have died. Fish can be rather finicky regarding their habitat so it is important to know the requirements of the fish you plan to keep and make sure to give them the correct living conditions for them to thrive. Water pH is one aspect of tank maintenance that is extremely important for keeping your fish alive. PH is the measure of a substance's acidity. It is measured on a scale of 1 to 14, with 1 being the most acidic and 14 the most basic. Pure water is neutral, meaning it has a pH of 7, but impurities can alter the pH and make it slightly more acidic or basic.


Step 1

Maintain a steady pH. It is important to keep the pH in an aquarium consistent even if it is not the exact pH that is best for a specific fish. Generally speaking, fish can survive in a range of pH levels, so as long as your tank is near the optimal pH, if you keep it regulated, your fish will live.

Step 2

Test the hardness of the water in your aquarium. Your tank's water has minerals naturally dissolved in it that act as a buffer to keep your pH stable. These minerals contribute to the hardness of the water. If your water is not hard enough, meaning there are not enough minerals dissolved, any steps you take to adjust your pH will yield only short-term results.

Step 3

Practice routine aquarium maintenance. Waste resulting from fish respiration and elimination releases phosphates into the water, which lower the water's pH. While it is often necessary to lower the pH of aquarium water, leaving waste build-up could lower your tank's water pH too much. It is important to routinely clean your filter pads and vacuum the gravel every time you change the water.

Step 4

Change part of your tank's water regularly. The water in your tank loses the ability to buffer and maintain a proper pH over time as acidic and basic ions are neutralized. You cannot change all the water in your aquarium with each cleaning because it could shock your fish, but replacing some of the water with fresh water will replace some of the ions, thereby restoring your buffer system and maintaining the proper pH.

Step 5

Use driftwood in your tank. Driftwood contains tannins that leach into the water and lower its pH. It is important to purchase driftwood that is safe for use in aquariums and properly wash it before use with water and a brush. Do not use any chemical cleaners or soap because they could poison your tank.

Step 6

Include peat moss in your aquarium. Peat moss is naturally acidic, so incorporating a small amount will lower your water's pH. It is important to start slowly and add only a small amount at a time so you don't lower the pH too much. You can either add the peat moss to the filter or put some in a small mesh bag and put it under the gravel.