The Ultimate Guide To Better Understanding Planted Aquarium Substrate Layers

Last Updated on March 8, 2022 by admins

Learn about the factors you should consider when choosing planted aquarium substrate layers.

Have you ever wondered what is put in the aquarium first? In most cases, the answer is not water, but the substrate. Its role is extremely important and can significantly affect the aesthetic appearance of your aquarium, as well as the health of your pets and live plants. There are a few things to keep in mind when choosing the ideal substrate for your tank, such as particle size, color, reactivity with water, and its effect on your aquatic pets and plants.

Stay with us and find out all the details about planted aquarium substrate layers.

What Is An Aquarium Substrate?

It’s pretty simple! Aquarium substrate is any loose material that makes up the bottom of the tank. This includes any material that makes up the base layer of the aquascape such as gravel, sand, etc.

Why Are Substrates Used; What Does The Substrate Do?


Good, quality, and healthy aquarium substrate enable proper nutrient circulation and root penetration. Therefore, it is necessary to take into account the size and shape of the particles of the substrate that we plan to use in the aquarium.

If the particles are too small, the plant will not be able to hold well with the roots in the substrate, and will therefore float away very easily if disturbed. On the other hand, too large and too sharp particles are not desirable. Using them you risk damaging plants and irritating / injuring your bottom-type fish.


One of the most important roles of planted aquarium substrate layers is nourishment. Most aquatic hobbyists use the Walstad method for recreation as close as possible to the biological, chemical, and mechanical conditions that plants have in nature.

A compound aquarium substrate, such as clay-soil-gravel, is most commonly used. Where one material provides filtration, another provides nutrients and the third acts as a sealing material.

Creates Balance

The aquarium substrate can be inert or active and directly affect the pH and KH of the water. For example, crushed corals are known to raise pH and KH, while peat moss lowers them.

Particle size also affects water balance, as larger particles allow more uneaten food and waste to slip by, resulting in increased ammonia and nitrite levels. On the other hand, smaller particles can become compact creating areas that lack oxygen. This condition promotes the growth of anaerobic bacteria and the appearance of toxic gas pockets of hydrogen sulfide.

Creates An Aesthetically Pleasing Appearance

Planted aquarium substrate layers have an aesthetic role as well. They can be in varieties of colors, shapes, and compositions. Furthermore, when it comes to colors, they can range from a completely natural look to those vibrant and bright colors.

The dark background helps to keep light-colored fishes stand out, and the light background makes your dark-colored fish look awesome and seemingly enlarge a small tank. What you choose depends on your preferences.

Planted Aquarium Substrate Layers; Which One To Choose?

Keep reading to find out which aquarium substrates are best for this purpose.


When they hear the word gravel, most people think of small pea-sized pebbles, which is actually not far from the truth. It comes in sizes ranging from 2 mm and 5 mm and is available in a wide range of materials as well. The best thing is that the gaps around each stone are small, so food and feces cannot fall as far.


Much like real sand from the beach, aquarium sand comes in a range of grain sizes, from coarse to fine. Sand, just like gravel, has little or no gap between each grain, so the remains of uneaten food, as well as feces, have nowhere to get stuck. All these specifications together make sand one of the most popular planted aquarium substrate layers.

Planted Aquarium Substrate Layers; Which One To Choose

Learn more about: How To Wash Aquarium Sand?

Crushed Coral, Limestone, Marble & Oolitic Aragonite

Every aquarist must be aware of the importance of maintaining a healthy environment for fish to survive and thrive. Therefore, substrates such as crushed coral, limestone, marble, and oolitic aragonite are excellent choices.

They have the ability to increase the pH and KH of aquarium water. Also, they are extremely popular due to their light coloration which shows all kinds of dirt, organic matter, uneaten fish food, and other biological leftovers.

Peat Moss

Did you know that there are almost 400 types of peat moss? Peat refers to all types of dead and decaying moss that accumulate over time at the bottom of an aquarium tank. It ranks high on the list of popular planted aquarium substrate layers for several reasons. Namely, it contains many nutrients and has the ability to prevent the growth and development of various algae.


Laterite is a clay-based substrate that is very rich in iron, but this, unfortunately, doesn’t apply to other nutrients. It is recommended to wash well with water before use and in combination with plain gravel.

Aqua Soil

Aquarium Soil is an excellent type of substrate, known for its various benefits associated with plant growth. When using it, it is necessary to pay attention to its compactness because it can create problems with circulation and change the chemical composition of water.

It is recommended to use it with a layer of gravel or sand on top.

In Conclusion

Each aquarium, around the world, has its own unique style and layout. The beauty of cultivating a planted tank is that you have so many options for customization. When choosing the ideal substrate, the most important thing is to pay attention to the needs of your fish and live plants, so that you can choose a substrate that meets their requirements, but still looks beautiful and unique.

We hope you found this article on planted aquarium substrate layers useful. What type of substrate do you prefer? Let us know in the section below!

Read more about How to Bring Up Alkalinity IN Aquarium?


How Deep Should Substrate Be In A Planted Tank?

It is recommended to have a layer of substrate that is at least 2-3 inches deep in your planted aquarium tank. Such depth will allow your rooting plants to grow sufficiently.

Can You Put Sand On Top Of Plant Substrate?

That's right, you can put sand on top of plant substrate. It is recommended that you never make a layer that is deeper than 1 inch, as this will prevent the substrate from aerating. The soil of your aquarium tank should never be too smooth.

Can I Mix Gravel And Plant Substrate?

If you want to use two types of substrates together in the aquarium, it is recommended to mix only those substrates of the same grain size. Therefore, you can mix them if the sizes match.