Limestone in Aquarium

If your Rocks are actually limestone, they are the cause of the pH elevation in your aquarium water. Limestone is calcareous (contains calcium) and is known for its ability to both harden the water and increase the pH.

Limestone is also used to remove excess iron.

From water in fish tanks, adding limestone in an aquarium will help clean up the water as limestone removes algae from the water.

Remember that limestone should only be placed in a fish tank where the High acidity levels and soft water harm the fish.

Raising pH with limestone

In addition to having the ability to raise pH, limestone contains calcium. Some prefer dolomitic limestone because it contains both calcium and magnesium, however soils high in magnesium (serpentine) Do not need more magnesium.

Limestone is a calcareous rock rich in carbonates (usually calcite), which give a pH of 7 and above. Sandstones contain much silica and so give rise to neutral or slightly acid soils, where the pH can be as low as 3.5.

It takes 20 to 50 pounds (9-23k) of group limestone per 1,000 square feet (93m) to correct a mildly acidic lawn.

Lime will react completely with the soil in 2 to 3 years after it has been applied; although, benefits from lime may occur within the first few months after application.

Type of LimestoneActive IngredientsMolecular formulaDefinition
Calcitic Limestone Calcium Carbonate CaCo3 Calcitic Limestone is calcium and it neutralizes Acids in the Growing
Dolomitic Limestone Calcium Magnesium Carbonate CaMg(Co3)2 It is a combination of Calcium Carbonate and Magnesium carbonate.

What is pH?

It is to express the acidity or alkalinity of a Sol on a logarithmic scale on which 7 is neutral, lower values are more acidic, and higher values are more alkaline.

Benefits of limestone Rock for Aquarium

Limestone is gold for your pet's aquarium, especially if dealing with saltwater fish. You see, there are several advantages to putting limestone in a fish tank, so let's take an in-depth look at some of them.

Aesthetically pleasing

Placing limestone in an aquarium makes the fish tank look life-like and beautiful. The natural look of limestone adds to the charm of any environment, but underwater limestone creates a dream-like appeal to your pet's habitat. The natural holes in the limestone provide a ground for your fish to play a game of hide and seek.


Even if you have a large aquarium, adding limestone to the fish tank will not be a hefty weight on your budget.

Clean the environment

Limestone is an alkaline agent, and placing limestone in a fish tank helps keep the algae away from the water.

Rocks that lower pH

Limestone is an alkaline agent that works to increase the pH levels of fish tank water. You see, limestone reacts with the acid in the water and neutralizes it. Limestone is seen as the easiest way to harden aquarium water.

Helps in the growth of fish

Limestone contains many minerals, especially calcium and phosphorus. And these minerals help in the growth of fish.