How to Raise pH in a Fish Tank – 6 Effective Ways!

When we talk about fisk tank maintenance, we cannot ignore its pH levels. pH is one of the most significant factors that impact the quality of the water in your fish tank.

If the pH level is too low, it can prove fatal for your fish. Therefore, raising and maintaining the pH of the tank becomes critical.

You must run regular tests to keep a check on these levels. If you find it to be too low, then there are many ways to raise it to a sufficient level.

Let’s have a look at 6 methods to raise the PH in a fish tank!

6 Ways to Raise pH in a fish tank

You can adopt any of the following methods to raise and maintain the pH.

Add Bicarbonates

Adding bicarbonates to the fish tank shows a significant rise in the pH content.

You can add the following to raise the pH levels in your aquarium:

  • Aquarium buffers: Aquarium buffers are available at aquarium shops and pet stores. They are rich in bicarbonates and sodium carbonate. Aquarium buffers raise the pH level much more efficiently than baking soda.
  • Baking soda: Baking soda contains bicarbonates, and you might already have it available in your house. Typically, the recommended ratio is 1 teaspoon of baking soda per 5 gallons. To raise the pH level steadily, dissolve the soda in some water instead of adding it in the tank water directly. Adding baking soda is not a one-time solution, you’ll have to continuously regulate the level of pH in the fish tank.

Be mindful of the way you add bicarbonates.

Adding too much soda or buffers can cause a sudden spike in the pH, which could kill your fish.

It’s best to take it slow to prevent shocking or stressing your fish with a sudden change in the environment.

Add Rocks and Substrates

You can raise the pH in your water tank by putting in a few rocks and substrates.

Some of the options are:

These rocks are readily available at pet stores. Make sure you remove your fish from the tank before adding any rocks or substrates to prevent harm to its gills.

If you don’t want these rocks to be on display in your tank, you can place them in a small bag and add it to the filter.

Again, be conscious of the sudden rise in pH and make sure you don’t overdo it.

Add Seashells

Seashells are naturally high in carbonate content, which is instrumental in raising the pH of water.

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You can collect shells from the beach or buy them from a store. Don’t forget to rinse them before adding to your fish tank.

For each gallon of water, you should add two seashells. The rise in pH might take a few days as seashells dissolve slowly.

Also, avoid painted shells as they can be harmful to your fish.

Change the Water Regularly

A very simple way to prevent the dropping of pH in the fish tank is to change the water regularly.

Consider changing it at short intervals instead of one large shift to prevent shocking your fish with a constantly changing pH.

Regular vacuuming of food and waste particles also makes a significant difference in keeping the pH from dropping over time.

Increase Aeration in the Fish Tank

Increasing aeration in the fish tank makes a massive difference. It increases the oxygen content, which leads to a decline in carbon dioxide.

The lesser the carbon dioxide, the higher the pH content.

Therefore, aeration is an excellent way to maintain a higher pH.

Remove pH lowering objects

Many objects contribute to the lowering of pH if you don’t pay attention.

For instance, a piece of driftwood could have a significant impact on the pH of your fish tank.

Most people usually use driftwood for decorative purposes, but it contains tannic acid, which lowers the pH of the water.

Removing the objects that contribute to the lowering of pH in the fish tank will help you maintain the pH levels.

How to check the pH levels of a fish tank?

To determine the need to raise the pH in your fish tank, you’ll have to first measure its content properly.

pH shows the number of hydrogen ions in water. You can dilute the water to reduce its pH.

Similarly, adding bicarbonates, hydroxides, and other compounds increases the pH.

pH can be calculated using aquarium test kits. These pH testing kits are available at local pet stores and online (you can buy this one).

Different test kits use different testing methods. Some testing kits change the color of water samples to display a certain characteristic.

While others can be dipped directly in the tank. The color on these strips is matched with an accompanying colored chart to determine the pH.

Digital testers are another pH testing device that gives fast readings. They are easy to use and calibrate. Digital testers are easily available online.

You should check the pH of your fish tank daily, weekly, or biweekly, depending on its alkalinity.

It’s important to remember that the test kits don’t always give an accurate reading.

Make sure you calibrate your testing kit before using it. If it’s showing an unusually high or low pH, then you should double-check with a new kit, just to be safe.

What’s the appropriate pH level for your fish tank?

The appropriate pH level of a fish tank varies and it depends on the kind of fish you have. There is no one-for-all solution. Freshwater fish require a different environment than seawater fish.

If you aren’t sure what kind of environment your fish belongs, you should consult the pet store that you bought it from.

You can also continue to maintain the same pH as the previous owner, as the fish is already adjusted to it.

There’s also plenty of information available online, concerning each type of fish. Several resources are available on social media groups, communities as well as local libraries.

Also read: How do Fish React to Low pH in an Aquarium?

How to lower the pH level in a fish tank?

Just as low pH is harmful to your fish, extremely high pH content can also be deadly.

If your fish tank is showing a high pH level, you can bring it down by adding the following things:

  • Peat moss: Adding peat moss in a fish tank can efficiently bring the pH level down. You can add it as a substrate or put it in the filter.
  • Carbon dioxide: As we mentioned earlier, a high concentration of carbon dioxide is the primary cause of low pH. So, by adding or increasing the content of Carbon dioxide, you’ll be able to lower the pH.
  • Driftwood: The tannins in driftwood bring down the pH levels in a fish tank.

Make sure you keep checking the pH to not lower it beyond a limit.

How does pH affect the water quality in a fish tank?

The pH of water impacts the water quality and chemistry in your fish tank in several ways.

Maintaining a healthy pH for your fish should be an utmost priority, as the inability to do so could have fatal consequences.

For example, if the pH of the fish tank goes below 6.0, the bacteria in the water will die.

These bacteria play an instrumental role in keeping the concentration of ammonia and nitrates low.

Nitrates and ammonia are extremely toxic to fish. It will trigger your tank to recycle so that the toxic elements can be eliminated.

This process can prove to be detrimental to your fish.

Low pH also accelerates the metal release from rocks and substrates, which can affect the fish’s metabolism and water intake.

On the other hand, if the pH levels rise above 12 – 14, they can harm the fish by damaging their cellular membrane.


The pH level of the fish tank plays a crucial role in the wellbeing of your fish. Although you should raise the pH level if necessary, make sure you do it gradually.

Rapid changes in the pH content can turn out to be deadly for your fish.

It is usually recommended to let your fish acclimate to the natural pH of the fish tank, instead of adjusting your water to fit its preferences.

However, if the pH is significantly lower than normal, then you must make adjustments.

Some fish owners prefer to give their fish an environment as close to their natural habitat as possible.

Then, the methods mentioned above can be used to achieve that.

Avoid fluctuating the pH in the fish tank and try to maintain it to a set level without causing shock or harm to your fish.

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