Ways to Lowering Aquarium PH Naturally

Aquariums make a beautiful addition to any room, home, or office, but in order to have a striking aquarium, first you need to make sure your fish and any live fauna are healthy. Water chemistry is very important for fish to be happy and healthy and certain chemicals need specific levels for each fish species to feel comfortable.

It is imperative when starting or continuing an aquarium to match fish with the similar water requirements. Meeting all the environment necessities can be a hard job and can take some time to figure out what works best for each aquarium.

Aaquarium PH

Causes of pH changes

The pH of the water is a very important parameter that has to remain constant, as acidic or alkaline water can harm fish, sicken them, or even kill them if their bodies are not built to withstand it. Newly added water, decorations, and even new plants can easily unbalance the pH. Some decorations can leak toxic chemicals into the water, so you have to make sure they are dyed with colorfast inks. Gravel can also effect the pH, depending on the type of gravel used. Even if you find a certain type of gravel appealing, make sure it is meant for your freshwater or marine aquarium.

Specific stones and rocks can change your water’s pH levels. For instance, limestone is a calcium-rich material that dissolves and mixes into the water, increasing the pH. Another reason is aquatic plants which trap CO2 and elements, such as nitrates that spike pH levels. Watch out for excess algae and slime decorations, rocks, and glass. An aquarium with excess algae signifies that the pH level is excessive, which most fishes dislike.

On top of that, an old or ineffective filter can negatively impact several ways. However, mainly it makes the pH level unfavorable for the fishes in the aquarium. Even fish waste and other broken-down material are also responsible for keeping pH levels elevated.

Tap water can contain alkaline compounds and metals. They cause a sharp rise in the pH levels of the aquarium. Moreover, placing the fish bag from the store or even placing your hand can significantly increase the pH levels. Hence, experts always recommend against using unconditioned tap water in aquariums.

Even adding untreated water from ground sources like boreholes in the tank may lead to a sharp rise in pH levels. Water from streams, ponds, rainwater, and borehole water have high alkaline or acidic levels, therefore not ideal for aquarium fishes.

Simultaneously, regular foods put into the tank are responsible for the increase in alkalinity levels in the water. Even the depletion of natural aquarium plants can reduce carbon dioxide levels in the tank, leading to a rise in pH levels gradually. It is vital to have and maintain natural plants in the aquarium to ensure a steady carbon dioxide supply all the time. pH levels can increase when you add different fish food in the aquarium, causing a rise in the alkalinity of the tank water.

CO2 escapes when aerating tanks which increases pH levels. This is why using an air stone is advised when you require to raise the water’s alkalinity. Airstone generally ranges between 4 inches to 2-inch diameters and usually weighs around 15 ounces. If your pH level is too low, remove the air stone so that pH levels can increase again. Remember that prices of air stone may be different between regions.

Furthermore, carbon dioxide becomes more available when replacing the old filter, thereby decreasing the pH level. Experts advise cleaning the tank frequently so that the aquarium is absolutely waste-free since several water filters don’t effectively remove all fish waste.

Many use driftwood to decorate their aquarium, but excessive use of them can decrease the pH levels more than required. However, it’s hard to deny that driftwood is also useful when the pH level is too high. Compounds known as tannins generally soften the alkaline, hard water. Also, one should not forget that the plant’s pH levels go up and down frequently.

Be very careful when changing the tank filter. Newly developed bacteria and substances in the filter can also effect the pH and make fish feel uncomfortable.

Effects Of Ph In The Aquarium

High Alkaline

Even a slight pH change in the aquarium water can lead to serious health impacts on the fish. Basic water rich in alkaline can negatively impact the fishes’ gills to a great extent. If you see the fish dart back and forth, make sure to check the pH of the water as it is a sign of high alkaline levels in the water, which may cause fish death.

High Acid

When fish live in an acidic aquarium, it can increase mucous production to a great degree. Mainly, it is the outcome of the rise in toxic elements backed by acidic aquarium water. Additionally, you should watch out for symptoms like fish gasping, eye damage, and hyperplasia (thickening of gills and skin).

How Are pH Levels Significant For Ensuring The Good Health Of Living Organisms In Aquariums?

There are not many reasons for increasing pH levels in your fish tank. The pH scale ranges between 1 to 14. Generally, the acceptable pH levels range between 6.8 and 7.6, while 7.0 is considered the neutral point.

One vital thing to remember regarding the ph scale is it is logarithmic. For instance, a pH level of 5 means it is ten times more acidic than a pH of 6, and a pH of 4 is 100 times more acidic than pH 6.

Therefore, when your fish can survive at a pH of 7, yet the water in the aquarium is at a pH level of 8, it means the water in the tank is ten times more alkaline than the acceptable pH level. On the other hand, when the pH is 9, the fish is living in water that is a hundred times more alkaline than the recommended measure for best health. Hence, it is clear that a slight change in the needed pH can contribute to unwanted consequences like the death of the fish.

Moreover, anticipating that a fish needs a pH of 8 to survive in the water with a fish that needs a 6 is not reasonable as both of them will be under huge stress. These examples intend to mainly highlight the significance of matching the fish close to the pH levels of the aquarium and then closely watching the pH levels.   

Essentially, the need for lowering or increasing the pH levels in aquariums is to ensure the best health of living organisms. It needs to be understood that plants and fish come from places with narrow water quality parameters.

For instance, Amazon Sword plants, angelfish, barbs, tetras, and more organisms from equatorial and tropical regions like Southeast Asia or Brazil thrive in acidic waters.

These fish and plants hail from streams, rivers, and lakes which flow through forests filled with dropped leaves, sticks, and driftwood rich in tannin. Hence, the soil too is rich in humus, tannins, and more organic materials.

In other words, tannins and more organic matter tend to increase pH levels towards acidity.

Even though the captive-bred aquarium fish are not so choosey, you will generally find good color and breeding behavior if you satisfy their pH requirements acceptably.

Natural ways to lower pH

You can keep an eye on the pH in your aquarium with various kits and tests provided at pet stores and there are chemicals that can lower or raise the pH according to the aquarium needs. The disadvantage of this is chemicals, added in large quantities, can cause high pH differences, which can do more harm than good. If you think of using these substances, be sure to add them gradually to help fish stay comfortable.

It is always better, and often less expensive, to naturally lower the aquarium pH.  Here are several ways to add environmental elements to your tank to assist with pH levels.


Driftwood can slightly lower the tank pH over time, but you must keep in mind it may also leak tannins into the water and give it a darker color, which is great if you have blackwater fish. To avoid tannin leaks, keep the piece of wood submerged in a separate container for a couple of weeks or boil it before adding it to the aquarium.

Wood can be a great water filter, but always remember to purchase it from a pet store and make sure it is for an aquarium, as pieces sold for reptiles can leak dangerous chemicals into the water.

Peat Moss

Peat moss can act as a natural water filter and help lower the tank pH.  Similar to driftwood, peat moss can also color the water, so it is recommended to leave it for a few days in a bucket of water. It is very important to use untreated peat bought from pet stores, as peat found at gardening stores may contain chemicals dangerous for fish or aquarium plants.

You can add peat moss in the tank filter as chunks or pellets using a filter bag or a piece of panty hose to keep it together and act as a second filter.

Leaf litter

Brown leaves can help lower aquarium pH, especially almond leaves, also known as Catappa leaves. They are considered the “poor man’s water conditioner” in India and placing them in an tank can also provide your fish with places for hiding, as well as, according to some, a natural anti-inflammatory and antioxidant.

Also, Indian Almond (Terminalia catappa) are very common in pet stores these days. Many prefer catappa leaves to peat in established aquariums. Similar to driftwood and peat, they slowly produce tannins when decaying. When turning the water brown, it aids in reducing and buffering the pH nearing acidity.

The natural visual appeal of these catappa leaves is loved by many, so they place them in choice locations to enhance the overall beauty of the aquarium. Eventually, they wander and get caught in currents that become natural sailboats for snails and shrimps.

Alternatively, you can bundle them and put them in the filter to continue adding tannin without wandering aimlessly.

They may also leak tannins, which are fine for river fish, but you may want to pre-treat it for a few days before adding it to the tank for other fish.


CO2 is great for keeping some live plants healthy and it also turns into carbonic acid to keep the pH level lower as well as keeping algae growth at a minimum.

Frequently Asked Questions

Do Plants Lower pH In An Aquarium?

Plants can decrease or increase pH levels in fish water tanks in various manners. It generally depends on the way you manage your actions. Even though carbon dioxide decreases the pH of water in the aquarium, oxygen doesn’t impact pH. That is why plants in the tank consume more carbon dioxide, which removes it from the water, leading to a gradual rise in the pH levels.

The removal of carbon dioxide has a slight but effective impact on pH levels. Apart from carbon dioxide, there are more compounds that plants can metabolize that have a huge impact on the pH levels of the aquarium.

Plants can usually absorb ammonia and other nitrogenous substances simultaneously. These nitrogenous substances can initiate numerous biological processes that produce free hydrogen ions, which decrease pH levels rather than increase them.

When plants absorb more nitrogenous substances from water, extra hydrogen ions are released into the fish tank water, decreasing the pH. Egeria is one of the famous water plant species that most experts recommend adding to the aquarium. This plant absorbs other ions like calcium that decrease water’s buffering ability to decrease pH levels.

Even though dead plants are known for reducing pH levels in the water, it is not the best thing to do. One should not forget that dead plants rot inside and disintegrate, generating a high amount of ammonia and other nitrogenous elements in the water, decreasing the pH levels. Besides, dead plants rotting inside the aquarium is not good for the fishes. Hence, it is crucial to remove the dead plants quickly. Also, change the water right away when you discover the dead plants in the fish tank.

Although plants can either decrease or increase the pH in the aquarium, high ph levels can impact the living plants to some extent. Similar to fishes, plants adapt fast to their local environment with time.

Do High Ph Levels Kill Fish?

When the aquarium fishes start behaving unusually, it may be a sign that the pH levels of the water are very high. In situations of high pH levels, the fish may seem sluggish, and their breathing in that water can become very difficult.

The rise of pH levels in the aquarium is called “Ick’ or “Ich” in fish. Such a disease can cause the death of the fish due to the absence of treatment at the right time.

You can easily identify the signs of Ick on your fish if you observe the development of small white spots everywhere on their body. Symptoms of infected aquarium fish are that they seem lethargic and have the behavior of scratching their bodies against the water tank walls. You may also find bloody streaks on the fish’s fins that indicate the same difficulty.  

Does Cleaning The Aquarium Lower The Ph Level?

Definitely, regularly cleaning and maintaining the aquarium is one of the best natural ways to ensure a low pH level. Most experts suggest that cleaning the fish tank every two weeks is a healthy way to keep the pH level low and ensure the best health of the living organism in the aquarium. Also, frequent cleaning limits the build-up of ammonia in the aquarium environment and is responsible for raising pH levels.  

While cleaning the fish water tank, ensure to remove all green algae from the walls of the tank by utilizing a proper scraper. Besides, it is vital to replace 205 of the tank water with fresh and clean water at a time. It is better to remove all the water at one time since it is quite unsafe. It’s advisable to use a recommended siphon to get rid of the gunk on the gravel exterior and other tank decorations.

It is also significant to clean all the gravel parts to clean the waste materials deposited by the fish. Even the leftovers and food particles should not be left out when cleaning. It is not required to remove the fish or any aquarium components when cleaning the space. Removing the fish from the water may become the cause of some diseases or the death of the fish.

When there is a filter inside the tank, check whether it is working properly or not. It is vital to make sure that it is neither dirty nor clogged, something that generally happens in a short time.

When cleaning the filter, just remove the component and then rinse them in the cool water below to clean the sticky debris and gunk. Also, go by the instructions given in the filter to ensure appropriate cleaning of the cartridge, carbon packet, and sponge.

In addition, you would want to replace about 10% of the fish tank water every day to ensure low pH levels. One can do this daily or once every 2-3 days. Utilize a siphon to replace the water and add fresh water immediately. The siphon method is considered the most convenient approach to replacing water from an aquarium without injuring the fish or breaking any accessory. Mainly, bowls and other ways lead to spilling of water and often cause damage to the water tank components.

Why A Ph Test On Your Aquarium Water Once A Week?

Performing a pH test on the waters of the aquarium every week will help you know the average pH differences in a month. One can easily do it by calculating the average. It is vital to understand the pH requirement of your fish, and conducting weekly tests will let you know whether the optimal range is maintained.

Why Is It Important To Cover The Fish Tank?

The main reason to cover the fish tank is to prevent pets like cats and dogs from drinking water. It can lead to food poisoning of your pet. Also, aquariums need to be covered because direct sunlight increases algae and allows foreign objects to enter the fish tank.  

Why Should You Avoid Vinegar In Lowering pH Levels?

Substances like vinegar should be avoided by all means because they are acidic. Moreover, vinegar can be too acidic and strong for the fishes in the aquarium. It can also cause the death of the fish. In other words, vinegar should be avoided at all costs, even if it is known for reducing pH levels in aquarium water.  

An aquarium is a lovely addition to your home or office. It’s like a small and beautiful marine world that offers excitement to the kids and visitors. The last thing you would want to see is dead fish floating in the tank. That is why it is important to monitor the pH levels in the fish water tank since the imbalance of pH levels can become the death of those beautiful fishes that you love to watch swim around.

The pH is very important, but you always have to keep an eye on nitrites, nitrates, ammonia, and other chemical substances in your tank as well. Good quality fish food also helps, as well as providing extra vitamins and minerals in order to keep your fish and plants healthy. Enjoy a healthy aquarium as a great decoration!

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