How To Maintain pH In A Discus Tank?

You can maintain the Discus pH level by combining Discus Buffer and Neutral regulator. The buffer stabilizes the pH in the reverse osmosis water and the neutral regulator acts flexible to keep the pH level under 7.0. All Discus keepers are advised to always have a good digital pH monitor.

There are no outlined steps for maintaining pH levels in a Discus tank setup. However, different methods and techniques exist. They include the use of vinegar, baking soda, rocks, substrate, aeration, etc. While some of these methods can effectively lower pH levels, others tend to increase them.

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What Controls Discus Water pH?

The pH of water is controlled and determined by acid-base equilibrium, but this balance is controlled by the presence of carbon dioxide. A decrease in the concentration of carbon dioxide increases pH level, while an increase will cause the pH to reduce.

There are various factors that affect water pH, these effects could either increase or decrease the level of pH in the aquarium.

What Causes pH To Rise?

The pH level rises due to a reduction in the level of carbon dioxide in the water, and this is caused by an excessive influx of oxygen into the water. Also, the use of substrate like crushed coral naturally increases pH level without harming the fishes.

Below are some of the elements that regulate the increase in pH:

  • Crushed coral-like substrate and ornaments would increase water pH.
  • Hard water generally has higher pH levels.
  • Addition of baking soda brings about a rise in water pH.
  • Addition of dolomites chippings.

What Causes Low pH In Aquarium?

The pH level in aquariums naturally reduces due to the consumption of oxygen by fishes and releasing of carbon dioxide into the water. When this occurs over time, the level of CO2 increases and a low pH level is observed.

Below are 9 factors that control the reduction of pH:

  1. Decreased aeration would lower water pH.
  2. Driftwood softens water and reduces its pH.
  3. Adding carbon dioxide to the water would lower its pH.
  4. High nitrates decrease pH levels.
  5. The presence of pollutants and waste would reduce water pH.
  6. Water purifiers can lower pH levels, they are however good with hard water.
  7. Soft water causes low pH levels.
  8. Reverse osmosis water has a pH of 6.0 and below.
  9. An overstocked aquarium can be low in pH.

What Is The Ideal pH Level For A Discus?

The ideal pH level required for a Discus is between (6.0 and 7.0) on the pH scale. It is advisable to maintain pH at a steady level within the ideal range, rather than allowing it spikes up and down.

Can Discus Live In Higher pH?

Yes, discus can live at a higher pH. for instance, is a pH of 8.2 too high for an aquarium? The simple answer is NO. Despite the ideal range for pH is between 6.0 and 7.0, higher pH levels are less harmful than lower pH levels because they are less acidic.

How Do I Lower The pH Level In My Discus Tank?

To reduce the water pH of your Discus tank, you can either make use of natural or chemical methods. All the same, the best way to lower pH in water is through the natural method because it increases the level of pH gradually.

Also, you can provide buffering by deionizing the water or infusing reverse osmosis to achieve the desired pH level. You can decorate your aquarium with driftwood and always ensure you test your water before adding it to the aquarium.

Natural Method

Under the natural method, we have peat moss, driftwood, catappa leaves, and reverse osmosis.

How To Use Reverse Osmosis To Lower pH Level?

Reverse osmosis lowers the pH level by forming carboxylic acids with carbon dioxide when exposed to air. This process provides a more neutral pH.

How To Use Peat Moss, Driftwood, Or Catappa Leaves To Lower pH Levels?

  • Step 1: Select the method you prefer to use (peat moss, driftwood, or catappa leaves).
  • Step 2: Pre-treat the peat moss by soaking it to reduce coloration.
  • Step 3: Add the pre-treated water gradually into the tank.

Chemical Method

Chemicals can be used to reduce water pH in discus tanks. One of such chemicals is vinegar.

How To Lower pH In Fish Tank With Vinegar?

Since vinegar is highly acidic, when diluted and added to the water tank, it helps lower the pH level from more alkaline to less alkaline or neutral. Ensure you remove the fish before carrying out the steps below.

  • Step 1: Remove the Discus fish from the water tank.
  • Step 2: Add vinegar at a rate of (1mL per gallon of water) per time.

    NOTE: A gallon of mixed vinegar and water should be added to the tank, and then, the fish should be placed back to adapt to that new pH before repeating it again.
  • Step 3: Place the fish into the tank.
  • Step 4: Repeat the process until the desired pH level is achieved.

Here is a video also explaining how to lower the pH in your Discus aquarium.

How Do I Raise The pH In My Discus Tank?

Low water pH can be increased or raised through the addition of carbonates like baking soda, crushed corals, and dolomite chippings into the aquarium.

How To Raise pH In a Fish Tank With Baking Soda?

Baking soda (sodium bicarbonate) has a pH of 8, which makes it alkaline in nature. It improves the clarity and stability when the right quantity is added to the aquarium, as it raises both the alkalinity and pH level.

Below are the steps to add baking soda to your aquarium:

  • Step 1: Remove the fish from the aquarium.
  • Step 2: Add (1 teaspoon) of baking soda to every (5 gallons) of water.
  • Step 3: Reintroduce the fish into the tank in order for it to be adjusted to the water.
  • Step 4: Repeat the process to achieve a constant 0.3 increase.


When considering the pH levels of your aquarium, always bear in mind that stability is the most important thing. The goal is to maintain a certain level of pH because an excessive change of the water pH would greatly affect your Discus.  


This is me Firas Sameer, the founder of, I am an aquarist guy with a passion and love for Discus fishes, I am learning every day with my hobby at home and sharing the things I am learning from my experience with you.

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