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How to Lower pH Level in Fish Tank

how to lower ph level in fish tank

An important part of the maintenance of your fish tank is familiarizing its water chemistry. If you think that you can just easily put whatever fish you like and add some decorations and accessories to the tank, think again. You need to consider the pH level of the water in the tank that it should have the accurate level to let the fish survive. The pH level can change every day; hence you need to monitor and adjust it according to your fish needs.

If the pH level is very high, you will need to know how to lower pH level in the fish tank. In a regular aquarium, the ideal pH level should be around 6.5 to 8.0 for the fish to live. However, there are other fish who likes low pH level while others want high pH level. In other words, there is no normal pH as it depends on the fish and where they originated, which determines their pH level preference.


What Causes pH to Rise in Aquarium

As I’ve said earlier, the pH level of your aquarium is not fixed. It may change any minute as several factors might cause it to decline or rise. In fact, natural biological processes are happening in the aquarium that causes the pH level to rise. For example, when plants in the aquarium absorb carbon dioxide and nitrates, which cause the pH level to decline, it will raise the overall pH level of the water. Also, those dissolve calcium-rich rocks and gravel can also help increase the pH level.

However, all the above-mentioned are natural causes that will help raise the water’s pH level. However, should you find yourself in a situation where the pH level is low, there are things that you can do to make it rise, such as changing the water in your aquarium. This method is the most effective way to raise the pH level if you need to. Another way is to add rocks or substrate in the aquarium can also help in raising the water’s pH level.

Adding baking soda can also raise the pH level in the water, but this should be done in moderation because too much of it might kill the fish in your aquarium. Adding shells and putting them in the aquarium can also contribute to raising the pH level of the water, even though you can also add chemicals that are commercially available that helps in raising the pH level of your aquarium water.

How to Reduce pH in Aquarium

what causes ph to rise in aquarium

On the other hand, if you find out that the water in your aquarium has a high pH level, there are some ways to reduce it. One of which is to add natural driftwood in the aquarium because it releases tannins that help lower the pH level of water. Meanwhile, you can also add peat moss or peat pellets to your filter to effectively lower the pH level of the water.

You can also add chemicals that are made to help lower the pH level of the water. There are many products available in the market that helps do the job, and buying one of them can help solve your problem.


Yes, driftwood is an effective way to lower your pH level but if you know what you are doing. Naturally, driftwood is an organic matter which means once it is submerged into the water, it can produce tannic acid that effectively reduces the pH level. However, the effectiveness of the driftwood in changing the pH level will all depend on the water hardness. If your water hardness is high, the chance is that it will resist the changes that the driftwood provides in lowering the pH level. Before putting driftwood in your aquarium, you will need to make sure that the water hardness is lower enough for the driftwood to be effective.

Peat Moss

Another way to reduce the pH level of your aquarium is to use peat moss. It has the ability to release gallic and tannic acid into the water, which helps in reducing the pH level. These chemicals will go after bicarbonates that are usually found on tanks with higher pH levels which helps in lowering the hardness and also the pH level.

But how to use the peat moss in the aquarium? The peat moss can be put inside the filter or outside the filter. You can also place it outside an aquarium in a different container but use water for the main aquarium. Another way to use pet moss is to use it as a substrate layer for the aquarium.

Peat Pellets

Using a peat pellet can also effectively lower the pH level of your aquarium. You can add a peat pellet to the internal or external canister. It will help in reducing not only the pH level but also the carbonate hardness. The peat pellets will release tanning to the aquarium to make them look natural and effectively lower the pH level. All you need to do is pre-soak the pellet for 1 to 2 days, adding to the filter. After soaking, you can rinse the tap water then add it to the filter of your aquarium.


One of the most common ways to lower pH levels in aquariums is using chemical solutions. Several products are being offered in the market that uses different active ingredients. Some products use diluted acids, while others use natural methods like tannins and other organic matter that come with acidic quality. Should you decide to use chemicals, my advice is to follow the label’s directions to achieve maximum results.


If you find out that the pH level of your aquarium water is so high, then learning how to lower the pH level in a fish tank is an essential skill for you. Even though some fish might need a specific pH level preference, having a stable pH is more important than looking for a specific value. Adjusting the pH level can be dangerous if you do not know what you are doing.

Also, unless you are trying to breed wild and sensitive fish that need extremely high or low pH levels, it will be better not to change the pH level of your aquarium. Most regular fish will I recommend following adapt to the water as long as it is well-maintained and clean while the pH level is stable. There is no need to change the pH level of your aquarium if the fish is alive, thriving, and showing no signs of stress.

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