6 Benefits Of Limestone In Aquariums

Last Updated on 2023-05-24

If you’re thinking about adding limestone to your aquarium, then you’ve come to the right place. In this article, not only will you find out about the benefit of adding limestone to your aquarium, but you’ll also learn about the potential problems and how it will affect the creatures in your tank as well!

So keep reading to find out everything you need to know!

Can You Use Limestone In An Aquarium?

Yes, you can add limestone to your aquarium, depending on the pH of the water currently. If the pH in your tank needs raising, then limestone is going to be perfect for this. However, if the tank already has a high pH level, then you should think twice before adding limestone, which may raise it higher.

What Are The Benefits Of Limestone In An Aquarium?

If you’re going to add limestone to your aquarium, then there are going to be a whole range of benefits that come from doing so! The benefits of doing so include the following:

Limestone Contains Nutrients Essential For Fish Growth

Did you know a fish’s nutrients don’t just come from the food it eats? A lot of minerals that fish need to grow actually come from the water itself. Minerals such as calcium and phosphorous are minerals fish need that are also found in limestone.

It Raises The pH In The Tank

If the pH in your tank is too high, then you should consider adding limestone to your tank as well. Limestone is alkaline, so adding it to your tank will slowly begin to raise the pH.

Excess Iron Is Removed From The Water

When water is too acidic, it’s going to contain a high amount of iron. Too much iron in the water is harmful to fish, and if left untreated, it can cause them to change color and become sick.

By using limestone to raise the alkalinity of water, you’re also going to be reducing the amount of iron in the water as well.

It Keeps The Tank Algae Free

Algae thrive in more acidic water. By adding limestone to your tank, you’re going to be raising the alkalinity, making the water a lot less habitable for algae.

Limestone Looks Nice

If you’re all about aesthetics, then limestone could work for you. Limestone looks especially great in natural tanks, and it will be a great addition to yours!

It’s Cheap

Limestone is not nearly as expensive as other fish tank decorations. So if you want to decorate your tank but if you’re on a budget, then you should definitely consider limestone.

How Does Limestone Raise The pH In A Fish Tank?

Because limestone is alkaline, it automatically begins reacting with the acid in your aquarium’s water, slowly neutralizing it. Because of this, it can be great for tanks that are acidic; however, if you have a tank that is already highly alkaline, then it could end up being harmful to your fish.

How Does Limestone Filter Water?

Limestone filters water by absorbing any contaminated water in the tank, as well as any iron in the tank as well. Not only does limestone filter water in freshwater tanks, but it filters water in saltwater tanks too!

How Do You Fix Low pH In An Aquarium With Limestone?

If you want to use limestone to fix low pH in your aquarium, then the solution couldn’t be simpler! You just need to buy limestone from any reputable fish store, give it a good wash, and then add it to your tank.

Over time, the limestone will begin to make the water more alkaline, and you’ll notice the pH rising. Just make sure you’re testing the pH often to ensure it doesn’t become too high.

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Here are some frequently asked questions people have about adding limestone to their aquarium!

Is Limestone Good For Nerite Snails?

Nerite snails thrive best in hardwater and water that has a pH above 7. So adding limestone to the tank is going to be great for keeping nerite snails healthy and happy.

Will Limestone In An Aquarium Increase Phosphates?

Instead of increasing phosphates in an aquarium, it’s been shown that when limestone is present, concentrations of phosphate become lower. So if you want high phosphates in your aquarium, make sure you don’t add too much limestone.

Is Limestone Good In A Planted Aquarium?

Aquarium plants need phosphates to thrive, and because limestone has been shown to decrease the amount of phosphate in the tank, it may be best avoided. This is, of course, unless you keep phosphorous in your tank topped up.

Is Limestone Good For Cichlids?

Whether limestone is good for cichlids or not depends on the type of cichlid. Adding limestone to an African cichlid tank is going to be great for them; however, adding it to an American cichlid tank could end up being harmful as they like soft water.

Is Limestone Or Shale Safe For An Aquarium?

Both limestone and shale are safe for your aquarium, but the one you should choose depends on your needs.

Will Limestone Deteriorate In An Aquarium?

While limestone is a durable rock, over time, it will begin to deteriorate. The rate at which it will deteriorate is even faster when it is left in acidic water, where it will begin to react with.

Should You Boil Rocks Before Putting Them In Your Aquarium?

It’s always a good idea to boil any decoration that you put in your aquarium. This way, not only will you kill any bacteria that may end up being transferred to the tank, but you’ll also kill any fungus or parasites that are on the decorations as well.

Is Limestone Safe For Shrimp?

Adding limestone to your tank for shrimp is completely fine in most cases. In fact, generally, shrimp tend to prefer slightly alkaline conditions in their tank. 

Is Limestone Toxic To Fish?

Limestone isn’t toxic to your fish, so you don’t have to worry about it poisoning them if you plan on adding some to your tank. However, it is important to note that limestone can raise the pH in the tank, which could be harmful to some fish.

Is Limestone Good For Fish Ponds?

Limestone is just as good for fish ponds as it is for aquariums. So if you’re thinking about adding some to your pond, you might as well go ahead and do so!


As you can see, adding limestone to your tank is going to have many great benefits for your fish. But you just need to make sure you’re keeping an eye on the water parameters to ensure the pH doesn’t become too high.

If you liked this article, make sure you check out the rest of the website! Otherwise, have a great day!

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