How to Lower pH in Fish Tank with Baking Soda

If you have heard about baking soda and its pH buffering effects, then you are in for a treat. This one trick, in particular, helps with pH balancing in your fish tank. Baking soda is sodium bicarbonate, which you are already familiar with anyway. All you need to do is add part of the baking soda when you are mixing up your tank water, whether your tank has fish in it or not.

So how does baking soda helps fight against the pH imbalance in your tank?

It works because the reaction that occurs when your tank water comes in contact with the baking soda. The baking soda dissolves into the water, creating sodium hydroxide ions. The sodium hydroxide ions will react with any hydrogen ions present in your tank water, neutralizing them. It will lower the pH, making it more alkaline.

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You can purchase baking soda at any grocery store. Not only does baking soda help to lower the pH of the water in your tank, but it also helps to promote good conditions in your tank. This article will break down how to use baking soda in an aquarium and highlight why you should be using it in your fish tank.

How to use Baking Soda to Lower your Aquarium pH?

child measuring baking soda for fish tank


  • One teaspoon of Baking Soda
  • 5 Gallons of water


The easiest way to use Baking soda is by adding it directly into your tank. Pour the baking soda into the tank water. The water will begin to fizz up, but this will go away after some time. Since baking soda is already sodium bicarbonate, most of it will dissolve into the water. It means that you do not need to worry about chemical reactions in your tank when using baking soda.

Some people like to use a siphon hose when adding baking soda into their tanks. Add a little bit of baking soda into a bucket using a measuring spoon. Then siphon this water into your tank.

Once the tank water comes in contact with the baking soda, it will dissolve. It makes sodium hydroxide ions, which neutralize any hydrogen ions present in the water. The result is that this lowers pH levels in your fish tank.

Benefits of Using Baking Soda in an Aquarium

Apart from lowering the pH in your tank, there are many other benefits to using this chemical in your fish tank.

It increases oxygen levels in your Aquarium

Baking soda helps to keep oxygen levels stabilized in your fish tank. This is because it helps break down harmful compounds that consume oxygen, such as ammonia and nitrates. It also removes carbon dioxide from your water by breaking it down in the process.

It removes heavy metals

You will notice that when your tank water becomes acidic, there is a lot of iron in the water. Baking soda helps to remove these metals by breaking them down into salt and water. This makes it much easier to filter out after the baking soda has done its job in your tank.

It Minimizes Cloudy Water

When your water is cloudy, you will notice many solids mixed in with the water. This means that you will often get cloudiness throughout your tank, making it more challenging to maintain suitable conditions in your aquarium. Baking soda helps break down the organics in your tank water, leaving it clear and easy to clean up after use.

It is Useful for Treating Fungus in Freshwater Aquariums

Fungus is one of the most disturbing things to deal with in an aquarium, especially if you are dealing with freshwater aquariums. Most of these fungal infections occur when the water has become stagnant, common in tropical fish tanks. Baking soda helps break down these pathogens, making it easier to clean up the mess that they leave behind.

It Minimizes Stress on your Fish and Optimizes their Health and Growth

By lowering the pH in your fish tank, you will notice that your fish and your aquatic life will respond positively to this change. They will feel more comfortable in this type of environment, which means that you will see them thrive and grow faster than before. Low pH levels mean less acidic and more alkaline, making it easier for fish to breathe in their surroundings.

Reducing the risk of infection as Baking soda is anti-microbial

Baking soda is one of the best ways to fight against bacteria, harmful in high concentrations. It acts by breaking down toxic compounds that promote bacteria growth, including nitrates and ammonia.

It also contains antioxidants, which are necessary for aquariums. These antioxidants help minimize the risk of infection in your fish tank because they will combat free radicals present in your water.

It Balances pH Levels

As mentioned above, baking soda helps to lower the pH in your aquarium. The downside of lowering the pH level is that if you go too low, you may kill off some of your tank fish because it can become too acidic for them to live in.

Ideal pH ranges for freshwater fish species

Fish species pH level
Goldfish 7.5
Guppy6.8 – 7.6
Cory Catfish7.0 – 8.0
Killifish6.0 – 7.0
Betta Fish6.5 – 8.0
Angelfish6.8 – 7.8
Neon Tetra4.0 – 7.5
Cherry Barb6.0 – 8.0
Oscar Fish6.0 – 8.0
Bristlenose Pleco6.5 – 7.5
Zebra Danio6.5 – 7.2
Platy6.8 – 8.5
Molly7.5 – 8.5
Discus6.0 – 7.0
Pearl Gourami5.5 – 7.5
Rainbowfish7.0 – 8.0
Green Swordtail7.0 – 8.4

Ideal pH ranges for saltwater fish species

Fish species pH level
Clownfish 7.8 – 8.4
Damselfish8.1 – 8.4
Green Chromis8.1 – 8.4
Cardinalfish8.1 – 8.4
Bicolor Blenny8.1 – 8.4
Clown Goby8.1 – 8.4
Yellow Watchman Goby8.0 – 8.4
Firefish Goby8.1 – 8.4
Hawkfish8.1 – 8.4
Lawnmower Blenny8.0 – 8.5
Diamond Goby8.1 – 8.5
Six Line Wrasse8.1 – 8.4
Royal Gramma8.1 – 8.4
Coral Beauty Angelfish8.0 – 8.4
Rusty Angelfish8.1 – 8.4
Dottyback8.1 – 8.4
Chalk Bass8.1 – 8.4

FAQs about Baking Soda and Fish Tanks

Is Baking Soda Safe for Fish?

The answer is yes. Baking soda is completely safe for your fish, as well as any invertebrates in your tank. Some people even use baking soda to lower the pH of their aquarium water before adding live plants. Plants will not grow well in acidic waters, but baking soda helps bring the pH levels to the perfect range that plants require. This helps to curb algae outbreaks, which are common in acidic tanks.

Does Baking Soda have a Particular Smell?

There is a slight smell to the soda, but it is not unpleasant. The reason can be because of the sodium hydroxide ions present in it. Even so, baking soda does not have a bad smell by any means.

Should you add Baking Soda To your Fish Tank when The Temperature is Low?

Baking soda does not raise or lower temperature, so there is no need to add it before your tank starts heating up. An excellent way to know if the temperature of your tank is okay is to look at your thermometer. You will need to add baking soda into the tank just before you add fish and each time after that.

Baking soda works wonders in lowering the pH levels of your fish tank. It is safe for fish and any other aquatic life in tanks, and it helps to promote healthy conditions in your fish tank. Remember that baking soda only lowers the pH of your tank water, but it can also help promote healthy conditions for your aquarium inhabitants. This article will provided you with the basics of using baking soda for its impressive benefits in your fish tank.


About Me

My name is Jason Matthews and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

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