How to Raise & Lower pH in Fish Tank With Baking Soda?

how to raise & lower pH in fish tank with baking soda

Keeping the pH levels in your fish tank at the proper level is crucial for the health and well-being of your fish. One simple and effective method is using baking soda.

So, how to raise & lower pH in fish tank with baking soda?

You can simply dissolve a small amount of baking soda in a cup of water and add it to the tank in small increments until you reach your desired pH level.

However, it should not be used to lower the pH. Instead, you can use natural methods such as adding driftwood or peat moss to the tank.

Keep reading to know more!

How to Lower and Increase Aquarium pH Level

What to prepare


  • One teaspoon of baking soda
  • Clean water
  • pH level test kid (optional)

Steps to raise aquarium pH with baking soda

Step 1: Calculate how much pH you need to raise


Before adding baking soda to your fish tank to increase pH in aquarium, it’s important to test the current pH level of the tank water with a water testing kit to determine the pH level you need to reach.

  • A general rule of thumb is to add one teaspoon of baking soda per five gallons of water to raise the pH level by 0.1.

Also, most freshwater fish are healthy at a pH level of 6.0 to 7.5, while saltwater fish are typically between 8.0 and 8.4.

Step 2: Dissolve the baking soda in water


It’s crucial to dissolve the baking soda in aquarium first before pouring it into the fish tank. This will help prevent the baking soda from clumping together and settling on the bottom of the tank.

To dissolve the baking soda, mix it with warm water until it’s fully dissolved.

Step 3: Add the baking soda slowly


Once the baking soda solution is ready, it’s important to administer it to the fish tank slowly.

Baking soda reacts so fast in the water, so adding it too quickly in the fish tank can suddenly alter the chemical composition of the water, which may harm your fish.

Start by adding a small amount of the solution to the tank and then wait for a few hours before testing the pH level again. Keep adding small amounts of baking soda until you reach the desired pH level.

Keep in mind that adding baking soda to fish tank also can increase alkalinity. Excessive water hardness and alkalinity can also be detrimental to the health of your pet fish. Therefore, you better maintain a proper balance.

Step 4: Maintain the right pH level

After you successfully raise the pH level in a fish tank to the desired level, it’s important to maintain it properly by monitoring the pH level regularly and making small adjustments as needed.

Ways to lower fish tank pH level


While baking soda can be used to increase the pH level in a fish tank, it is generally not recommended to use it to lower the pH level. So when noticing some symptoms of low pH in your fish tank, you can apply the following methods to decrease the pH level:

1. Use a pH down solution:
These are commercially available products that are specifically designed to lower the pH level in a fish tank. Be sure to follow the instructions carefully and make gradual adjustments to avoid shocking your fish.

2. Add natural materials:
Materials like driftwood, peat moss, or almond leaves to the tank can help lower the pH level naturally. Peat moss, for instance, works effectively in removing certain contaminants from water due to its ability to absorb and trap impurities.

3. Use vinegar:

If you are looking for the fastest way to lower the pH level in the aquarium, you can try using vinegar. No more than 1 mL of vinegar per gallon of water. However, you should apply this method with caution because it can be harmful to fish.

4. Reverse osmosis (RO):

The RO process works well in removing minerals and other impurities from water, which can decrease the pH of the water. However, the extent to which the pH level is lowered will depend on two factors including the quality of the RO system and the starting pH level of the water.

Frequently Asked Question


What is the ideal pH for a fish tank?

The ideal pH level ranges for fish in a freshwater aquarium: Most freshwater fish prefer a pH range between 6.0 to 7.5.

Fresh fish speciesIdeal pH range
Neon Tetra6.0 – 7.0
Guppy6.8 – 7.8
Betta6.5 – 8
Angelfish6.5 – 7.1
Corydoras Catfish6.5 – 7.8
Discus6.0 – 7.0
Swordtail7.0 – 8.4
Cherry Barb6.0 – 8.0
Mollies7.5 – 8.5
Goldfish6.5 – 7.5

The ideal pH level ranges for saltwater fish: The ideal pH range for a saltwater aquarium is typically between 8.0 and 8.4.

Saltwater fish speciesIdeal pH range
Clownfish8.0 – 8.4
Tang8.0 – 8.4
Goby8.0 – 8.4
Butterflyfish8.1 – 8.6
Blenny          8.2 – 8.4
Damselfish8.0 – 8.4
Wrasse          8.1 – 8.4
Seahorse8.1 – 8.4
Triggerfish8.2 – 8.4
Hawkfish8.2 – 8.4

What happens if pH is too low/high in fish tank?

If the pH is too low, meaning it’s too acidic, it can cause harm to the fish and other living organisms in the tank. A low pH can result in difficulty breathing, stunted growth, and even death for fish. If the pH level is too low, one way to address this is to raise alkalinity of the water by adding a buffer solution, such as baking soda.

The same goes for if the pH is too high, meaning it’s too alkaline which can cause damage to the gills, fins, and skin of fish. In addition, a high pH can lead to the growth of harmful bacteria and algae.

To prevent these issues, it’s crucial to fix pH levels in fish tank immediately whether it’s too low or too high, to maintain a healthy pH level.

How long does baking soda take to raise/lower pH in aquarium?

There is no accurate answer to this question. Normally, it takes about 15 – 30 minutes for baking soda to raise pH in aquarium.

However, it can vary depending on several factors, including the tank’s size, the amount of baking soda added, and the water’s initial pH level. Sometimes, it can take a day for the baking soda to fully dissolve and have an impact on the pH level.

It’s essential to monitor the pH level regularly after raising pH in aquarium to ensure that it remains stable and does not fluctuate too rapidly.

How much baking soda to add to fish tank?

Generally, it is recommended to add one teaspoon of baking soda per 5 gallons of water to raise the pH level by approximately 0.1.

For example, if you have a 20-gallon aquarium with a pH level of 7.0 and want to raise it to 7.5, you may need 5 teaspoons of baking soda.

You need to know that, the amount of baking soda to add to a fish tank to raise pH levels depends on several factors, such as the size of the aquarium and the current pH level. You should start by adding one teaspoon of baking soda. Wait for about 30min and then check the pH level again to see if it has reached the desired level.

How often should I put baking soda in my fish tank?

The frequency of adding baking soda to a fish tank to raise the pH level will depend on how quickly the acidic level in the tank returns to its previous levels.

You should monitor and test the pH level regularly to determine the appropriate frequency of adding baking soda.

Keep in mind that adding baking soda too frequently or in excessive amounts can also lead to negative consequences such as pH level fluctuations and alkalinity imbalances.

Therefore, it’s crucial to observe and make any change pH of water for fish. Remember to add baking soda in small amounts based on the test results. Gradually increasing the amount of baking soda over time and monitoring the pH level can help to ensure that the pH level stays stable.


How to raise & lower pH in fish tank with baking soda? Baking soda can be useful in adjusting the pH levels of a fish tank. To increase the pH, start by testing the water and adding baking soda gradually in small increments while monitoring the pH until it reaches the desired level.

When lowering the pH, other methods, such as using driftwood or adding peat moss, can also be more helpful in achieving the desired level. It is also important to know that each fish species has its preferred pH range.