How to Lower pH in Aquarium? (Complete Guide)

Maintaining water quality is one of the significant factors when it comes to taking proper care of your aquarium pet. pH is one of the key water parameters. The pH of tap water we usually use consists of a high pH level and is not always suitable for the fish that we keep in our aquarium.

Therefore, every aquarist or aspiring aquarist should know how to change and manipulate the pH level. So in this article, we will talk about how to lower pH in the aquarium! Let’s get started.

What Do You Need to Know About pH?

pH is an acronym for the “power of Hydrogen”. The pH scale ranges from 1 to 14. When the pH is 7, the water is considered being Neutral. When pH is greater than 7, it means the water is basic. If the pH is less than 7, it means the water is acidic.

Different kinds of fishes originate in different places which have different pH levels. So the suitable pH levels for fish are varied because of their species. For instance, saltwater fish prefer a pH level of 8.0 and above. African cichlids also often come from the lakes that have a pH level of above 8.0. The tropical fish from Brazil may live in acidic water that has a pH level of 5.5 or lower.

Maintain The Ideal pH in Aquarium

Most of the time, pH can be changed, and when it does, it affects both young and sick fish. A particular species of fish breeds at a pH level that accommodates them. Therefore, if you have the intention of getting a new aquarium, knowing the pH level of the water source is essential. It will enable you to know if it is suitable for the particular species of fish you want to keep. This is because some fish like Discus, and other cichlids, find it challenging to grow in a very narrow range of pH. This needs to be putting into consideration while setting up an aquarium.

When you are changing the fish aquarium by moving them from one aquarium to another, it is essential to note the pH level and match it. Because sudden changes in pH level can sometimes cause danger for the health of fish. Some fish like Neon tetras are usually sensitive to change of pH. So you should take it into account when changing the aquarium.

Checking and testing pH is very important. You should test it twice in a month or once a week. This will allow you to detect any strange act before it becomes problematic or more worsen. When the test has been carried out, it is crucial to keep the record in the record book for future purposes.

pH can change within some days and carrying out an inspection on them at a different time of the day can bring different outcomes even if there is nothing wrong. Thus, testing should be carried out in the afternoon.

If you detect something suspicious happening or the death of a fish, it will be wise to test the pH. If you use a chemical to treat the tank, there is a need to check the pH when the treatment began, and the last day of the procedure, also after a week.

You should test the water before purchasing a new fish. While buying you should ask about the species and origin locality of that fish as this will enable you to know what their water pH is. You should maintain the optimum pH for your new fish in the aquarium.

What to Check Before Lowering  pH in Aquarium:

If the fish is not growing properly or you found in the test that something is wrong like rising or dropping the pH suddenly, it needs to be attended immediately.

If it is necessary to lower or raise the pH of local tap water, you can visit the pet markets where commercial products that are designed to modify the pH level. But proactive water is the best you can rely on.

To keep a water pH level stable, you will need to adopt the method of changing the water frequently. You should vacuum the gravel as well.

As time goes by, the filter that breaks down the waste from the fish will make utilization of the alkalinity inside the water. It lowers the pH level gradually and the water becomes acidic. This can be prevented by changing the water that has a lower pH level with new dechlorinated water which contains high alkalinity. It will stabilize and improve the pH level. Many fishkeepers usually test their tap water for pH immediately. But, this cannot determine either the water is suitable for the fish or not.

To properly check and know the pH of your residence’s tap water, pour some of it in the container and put the air stone in the container to shake up to the surface, then allow the water to sit out for 24 hours. After this, you can now test the water for its pH.

It would be great if you can check it after 48 hours to see if it has come up with any changes. Therefore, tap water can be successfully checked for pH after being measure within 24-48 hours. It will give an accurate measurement of the actual pH of your tap water.

If you realize that your fish suddenly get sick, inactive, or even started dying this may be a result of a high pH level in the aquarium. It is suggested to test the pH level so that you can take proper steps accordingly. But if you have already checked the pH level and realize that it is higher than the usual so, lowering the pH should be the only option.

7 Ways To Lower pH level in Aquarium

Now, we will discuss 7 easy ways to lower the pH level in your aquarium:

1. Make sure to perform partial water change regularly

One of the main reasons why your aquarium water pH is high is because it always elevated ammonia. That’s why it’s ideal to change the water regularly to eliminate the fish waste and the leftover food from the tank. While changing the water, keep in mind to clean the gravel and decorations as well. This will help you to remove debris and algae.

2. Get a brand new filter

Maybe it is time to replace your filter if the one you are using cannot efficiently filter the water in the aquarium. You shouldn’t separate the sludge off when cleaning your filter while you are trying to eliminate the trash. Because the bacteria on the filter is necessary to maintain balance in the fish tank. Also, it is preferable to use water to clean the filter instead of using different chemicals.

3. Add peat moss

Adding peat moss is the standard way of lowering the pH. It is also the productive method to lower pH naturally in a tank as adding peat moss can astonish your fish. Peat moss can be added in different ways. But the most common way of adding it is direct to the filter. In this way, it will lower the pH of every water passed through the filter. Aside from that, it is also useful if you can place it in any area within the tank. If it is not placed or fixed inside the filter, it will float. Therefore, do not just drop the peat moss in the tank.

4. Add driftwood to the aquarium

Since driftwood can naturally be found in the water bodies. Thus adding them to an aquarium will bring out an ideal condition that is similar to the fish’s wild habitat. Therefore, when using driftwood, adding two sinewy driftwood will assist in filtering the water in your fish tank. Driftwood will add a more refreshing look to your fish tank. Not only that, but it will also help in releasing a large amount of tannin that will lower your pH water.

But before you buy driftwood to put in your fish tank, there some vital steps you will need to take. Although driftwood does not contain any contaminant that could be dangerous to the water. It’s still important to wash it properly. If not, it can change the color of your fish tank suddenly. A sudden change in the color of the water can be dangerous and harmful too for the fish. Also, make sure to boil the driftwood before putting it into the tank. It will kill any substantial detriment algae or fungi or algae that might come with the driftwood.

5. Add almond leaves

To maintain the pH at the optimal level, almond leaves are a perfect choice and remedy. The way to add almond leaves to the fish tank is simple, straightforward and it is safe for the fish. Almond leave has different natural components that can reduce the pH level in the fish tank fast and accurately. Not only they have the right nutrients, but almond leaves also have healing and impending certain fish diseases. Also, some of the fish that love to hide, it will serve as a harbor for them. Almond leaves contain anti-inflammatory and antioxidant components. Therefore, using almond leaves will also make your aquarium seems refreshing.

Before adding the almond leaves to your fish tank, you should soak it to avoid them adding color to the fish tank. Although, if to compare the changes that peat moss and driftwood will add to the water, the changes that almond leaves add to the water is hardly noticeable.

6. Reverse Osmosis

Using this method, it requires removing ions and molecules from the fish tank to make the water to be cleaner. When using the partial semi-permeable filter, most of the contaminants in the water are removed with the Reverse Osmosis Process. Small ions can pass through the RO filter, but it will render the heavy ions that can harm your fish.

Although this method might be quite expensive, it is also one of the most effective ways to lower the pH level in the fish tank. It can give more effective results than other methods. If you use this method to lower the pH in aquarium, you should replace the filter regularly.

If you have been using hard water for your aquarium, reverse osmosis will make sure the pH levels of the tank is optimal concentration. Still, reverse osmosis is only suitable for a bigger aquarium because it works in a bigger picture more effectively.

7. Reduce of aeration in the tank

Reducing the oxygen level in the aquarium is also one of the keen effective ways to reduce the pH level in your fish tank. Lowering the oxygen level will result from increases in carbon dioxide levels. This method is also one of the costly ways. It requires extra care because the fish need oxygen to survive. If the oxygen level is lower than the average standard, all the fish in the tank might end up dying. So you should apply this method carefully.

Thus, it is essential to consider the current condition of the fish before adding or altering the pH levels in the tank. Also, it will best if you apply the most natural methods to lower your pH level because “Less Use of Chemicals means more Use of Nature”. Some of the chemicals used to reduce the pH level can be harmful to the fishes and their health. They can either make them sick or kill them. Maintaining the optimal pH level is essential for the fish. Although keeping a constant level of pH can be hard, you can make it successful by applying the above method.


So keep in mind all these methods and keep checking your aquarium’s pH level regularly and ensure the safety and health of your fishes. If you follow the tips, you can lower the pH in the aquarium successfully. If you have any questions, let us know in the comment section below!

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