5 Ways To Raise pH In An Aquarium (& 5 Causes)

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Last Updated on 2023-11-16

Low pH in aquarium water can harm your fish. To raise pH in the Aquarium, try changing and aerating the water, adding baking soda, boiling driftwood, or using crushed coral in the filter.

Read on to find out more about raising the pH in your aquarium and how you can check and monitor the pH levels. Happy reading!

Key Takeaways:

  • Common low pH causes: poor maintenance, acidic tap water, insufficient air circulation, excess tannins, and infrequent water changes.
  • Solutions include better maintenance, testing and treating tap water, improving aeration, and pre-treating driftwood.
  • Monitor pH using digital meters, test strips, or liquid tests.
  • High pH may alter fish behavior and promote algae growth.
  • Low pH can stress fish and cause them to stay at the tank’s bottom or top.

What Causes Low pH in an Aquarium?

There can be many reasons behind a low water pH in your aquarium. These range from excess tannins in the water to poor maintenance and cleaning. While the reasons can be many, it is important to diagnose the problem behind low pH correctly so that you can work on the solution as soon as possible. Here are some common reasons.

1. Lack of Maintenance and Cleaning

Not maintaining and cleaning your aquarium properly is one of the most common reasons behind a low pH. Cleaning your tank regularly is something you shouldn’t skip as it can cause many other problems besides lowering the pH. 

So how exactly does a lack of maintenance lower the pH of the aquarium? Over time, fish waste, leftover food, and other contaminants can accumulate in the aquarium. If they’re not removed on a regular basis, they can lower the pH of the water.

2. Acidic Tap Water

Another cause of low pH in the aquarium is acidic tap water. This problem isn’t common in the US since tap water is rarely acidic, but in some places, it can be an issue.

This happens when you’re replacing the water in your aquarium with tap water, and the tap water is acidic. Once acidic water enters the aquarium, it can significantly lower the pH of the aquarium as well. 

To avoid this problem, make sure you get your tap water’s pH tested before using it to change your aquarium’s water.

3. Poor Air Flow and Regulation

If the air in your aquarium isn’t properly circulating throughout the water, it can lead to a decrease in the pH of the water

Sometimes the best thing you can do is get an airstone to help get the water circulating again.

 This happens when carbon dioxide (which is acidic) produced during fish respiration builds up in the water.

You can easily solve this problem by using a filter in your tank and making sure it works properly. Filters facilitate the movement of water and allow gas exchanges to take place, keeping pH levels stable.

4. Excess Tannins in the water

Tannins are acidic organic compounds that can lower your aquarium’s pH. These compounds are produced by wood decoration pieces, particularly those made from driftwood. If your aquarium has an excess amount of tannins, the water will turn slightly brown, and the pH will drop.

To prevent the water in your aquarium from turning acidic due to tannins, make sure you boil driftwood before putting it into your aquarium. Boiling driftwood will release the tannins.

5. Not Changing the Water Regularly   

If you don’t change your aquarium’s water regularly, the water can turn acidic slowly over time. Fish waste, dead plant matter, and leftover food can accumulate over time and lower the pH of the water.

Thus changing the aquarium water is necessary, and ideally, 15 to 20 percent of the water should be replaced every week. If your tank is lightly stocked, you may change the water once every two weeks.

Causes of Low pH in an AquariumSolutions to Low pH
Lack of Maintenance and CleaningRegular Cleaning and Maintenance
Acidic Tap WaterTest Tap Water pH and Treat if Necessary
Poor Air Flow and RegulationImprove Water Circulation and Aeration
Excess Tannins in the WaterBoil Driftwood Before Adding
Not Changing the Water RegularlyRegular Water Changes, 15-20% Weekly

How To Check The Ph Levels Of A Fish Tank

Having a steady pH in your fish tank is important in allowing the fish to grow and thrive. The pH of the water can change due to a number of reasons, and monitoring it regularly is important. Here, we mention some ways in which you can check the pH levels of your fish tank. We’ve also included some signs that indicate a higher-than-normal or a lower-than-normal water pH.

1. Using a Digital PH Meter

Using a digital pH meter is one of the easiest and most accurate ways of measuring the water pH in your aquarium.

Digital pH meters have probes or electrodes that dip into the water and measure the pH of the water quickly and accurately. These instruments are easy to use and give you a clear picture of the pH conditions in your aquarium.

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2. Using Test Strip Tests

The next method for testing the pH of your fish tank that we’re going to talk about is using strip tests. As the name suggests, strip tests come with a special strip that can be dipped into a sample of your tank water.

The strip will then change color, and you can refer to the color chart in the strip test kit to find out the corresponding pH for that color change.

API 5-IN-1 TEST STRIPS Freshwater and Saltwater Aquarium Test Strips 100-Count Box
  • Contains one (1) API 5-IN-1 TEST STRIPS Freshwater and Saltwater Aquarium Test Strips 100-Count Box

3. Using Liquid Tests

Liquid tests can be used to measure the pH of your aquarium’s water too. Like strip tests, they’re easy to use and produce quick results. To use a liquid test correctly, fill the provided container with some water from your fish tank and add the specified number of drops of the reagent to it.

Wait for a few minutes while the color change takes place. Refer to the provided color chart to find out the pH of the water.

API FRESHWATER MASTER TEST KIT 800-Test Freshwater Aquarium Water Master Test Kit, White, Single, Multi-colored
  • Contains one (1) API FRESHWATER MASTER TEST KIT 800-Test Freshwater Aquarium Water Master Test Kit, including 7 bottles of testing solutions, 1 color card and 4 tubes with cap

4. High pH Signs

If your aquarium’s water has a high pH, you’ll be able to observe changes in the fish and the environment of the tank. Your fish might try to swim near the surface of the water and swim in a random and chaotic manner.

They might also appear to be tired and may have trouble breathing. In the tank itself, you’ll notice a rapid increase in algae growth, particularly on the walls of the tank.

Now, check out this video by Long Island Fish Guy on how you can raise your Aquarium’s pH levels!

Symptoms of Low pH in a Fish Tank

If you’re still not sure whether you’re dealing with high pH in your fish tank, here are some of the most common signs to look for!

Algae Growth

Algae thrive in low PH waters, so if you’re noticing a spurt in Algae growth in your fish tank since the last time you cleaned your aquarium or if it’s beginning to falter vision from the outside and the inside, maybe it’s time to consider that your tank may be running on a low PH.

Stressed Fish

This is an obvious one, as your fish are the primary component of your aquarium. If they seem to be stressed or irritated and are generally staying at the bottom of the tank or swimming to the top, it may be an indication that they are struggling to breathe. This is a common sign of a deviation from a healthy pH.

Pale Fish

When the PH levels drop, the metabolism of the fish drops, depending on its species. This can cause the onset of a condition called Autophagy, where the organism begins to break down the cells of the host. As a result, the fish may begin to look paler than usual. This usually indicates that something isn’t right.

Staying Near The Bottom Or Top Of The Tank

You may also notice that your fish are spending a lot more time at the bottom or the top of the tank. Of course, this is fine if your fish are supposed to be there, but when they’re not it could be a sign of a pH problem.

When the acidity in the tank is too much, it’s going to cause your fish to either go to the top to try and find cleaner water, or sink to the bottom.

Is Low pH Bad for Fish?

Now that we’ve talked about the possible reasons behind a low water pH in your aquarium, it’s time to find out the impact a low pH can have. So, is low pH bad for your fish?

The answer depends on how low the pH is. If the pH is slightly lower than the optimal pH (between 6.8 and 7.8), then your fish won’t be affected. In fact, some species of your fish might be able to withstand slight fluctuations in the pH.

But if the pH in your aquarium is too low below the normal level (below 5.5), then it can bring about many health problems in your fish if prompt action isn’t taken to fix it

However, the most important thing to remember is the following:

It’s always better to have a low but solid pH that doesn’t fluctuate, over a pH that is constantly fluctuating. And always check the pH your fish need, as some naturally need a low pH.

To help you out I’ve created a complete guide on the water parameters of over 340 fish for your aquarium!

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Here are some commonly asked questions that people have about the pH levels in their tank.

How To Raise Ph In Saltwater Aquarium?

There are several ways to raise the pH in a saltwater aquarium. Such as

  • Using decorations that release alkaline compounds into the water
  • Change the water regularly
  • Add an alkaline buffer to the water
  • Use carbon dioxide scrubbers to absorb the gas

How To Raise Ph In Aquarium Without Chemicals?

Raising the pH in an aquarium without chemicals is certainly possible, and there are many ways to do it. Such as changing the water, aerating it, boiling pieces of driftwood, and adding crushed coral to the water.

Final Thoughts

A low pH in an aquarium can be worrying as it can lead to many health and environmental problems in the tank. There are many reasons behind a low pH, including lack of cleaning and maintenance, not changing the water regularly, and a lack of air circulation. There are many ways to fix this and raise the pH, such as replacing the water, aerating it, and adding baking soda and crushed coral.

In this guide, we’ve included everything you might want to know about raising the pH in your aquarium, and we hope you find it useful!


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