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How To Build Up Aquarium Substrate: Here’s How

how to build up aquarium substrate
If you love fishkeeping, then you probably also love decorating your aquarium! The best part is building the substrate because you have so many choices when it comes to materials, and a well-built substrate will help your tank thrive. How do you build up an aquarium substrate?

To build up an aquarium substrate requires many layers. You will need a base, porous substrate, additives, sand, and soil. While decorating, it’s helpful to keep your layers separated with nets. Doing so prevents the layers from compacting and mixing over time.

This article will discuss how to build up your aquarium’s substrate, including several factors that come with choosing materials and making layers. There is a lot of information to know, so let’s begin.

What’s a Cation Exchange Capacity (CEC) and What Does It Have To Do With Aquariums?

The Cation Exchange Capacity (CEC), which shows the ability of a material to hold nutrients, has a significant impact on your aquarium’s environment. When making a planted tank, you need to know what your substrates’ CEC is. Different levels make it harder for plants to absorb them through their roots.

Anything with a high CEC level is going to help your plants grow quickly. You will want to consider how many plants you want your tank to have. Some people prefer using items with low CEC so that their aquariums don’t become overtaken by plants.

However, the amount of plants you prefer in your tank is up to you! You should also consider what type of environment will make your fish the most comfortable.

Keep in mind that CEC represents how the substrate holds nutrients and not how much nutrients the substrate contains. You want to find something that has plenty of food for your plants as well.

What You Need To Build Substrate Layers?

To start building your substrate, you want to have plenty of materials on hand. Styrofoam for the base, porous substrates, gravel, and sand all build the foundation for a planted substrate. However, you need to stack them so they don’t combine over time, which you can do in many ways.

Before building your layers, you will need to make sure you only use quality substrate materials. You can use anything you like, as long as it is not harmful to your fish species. Here is what you need for a planted tank:

  • Styrofoam plates (base)
  • Porous substrate
  • Additives
  • Protractor and nets/mesh
  • Sand and soil
  • Decorations
  • Plants
  • Spray bottle with water

Types of Substrates

There are many types of substrates. While gravel and sand are the most popular, you can also find peat, aquarium soil, limestone, and more options. Each material impacts the pH of your water differently and has a varying CEC level. Knowing what to use when is essential for building substrate.

You can use several different kinds of materials to create your substrate. You want to consider options that work well together.

  • Gravel and Sand: Most tanks will use these materials, because gravel is easy to clean, and sand is safe for almost every fish species. They look natural and come in several different colors and sizes. These materials will not impact the pH levels of your tank and have a low CEC.
  • Crushed Coral, Limestone, and Aragonite: These minerals will raise the pH level in your tank. Fish keepers recommend them for African cichlids in freshwater tanks and most species in saltwater tanks. These materials are lightly colored, so they do show debris easily. If you want a dark substrate for African cichlids, consider using CaribSea Aquatics Eco-Complete Sand.
  • Peat: Peat is decomposed plant matter and including it in a planted tank comes with several benefits. It contains tons of nutrients, softens the water’s pH level, and has a high CEC. Peat is excellent for planted tanks, but it contains high amounts of tannins, which can darken your water.
  • Aquarium Soil: This type of soil is not what you’d find in your yard! Manufacturers treat aquarium soil, so it does not have harmful bacteria or parasites, and is fantastic for growing plants, as it has a high CEC. You need to ensure you apply it correctly, or the material can cause issues. Try using it under a layer of sand or gravel.

There are many options when it comes to building your substrate. You will want to spend a lot of time thinking about the materials to use when planning your decoration layout. However, many people enjoy choosing the substrate. There are many different colors and options — you can genuinely make a tank your own.

Choose Your Tank Decoration Style

There are three different tank decorating styles to choose from: Nature Aquarium, Iwagumi, and Dutch Aquarium. Each focus on different design themes, but all can produce a stunning tank. To choose your aquarium style, know more about the options you have, but many people take some elements from each.

Each has its own approach to arranging a tank. This section will briefly cover the styles’ main characteristics to give you an idea of what they are, as the techniques all have their approach to building the substrate foundation.

Nature Aquarium

The Nature Aquarium style focuses heavily on creating a natural environment for your fish. Many people create mountains, hills, valleys, beaches, and jungles using this style. Any tank that looks like a glimpse into a real pond is likely made of this style. However, there’s more to it than that.

While this style may seem random, everything aquarists place is to make it look as natural as possible. They spend a lot of time carefully arranging all the items inside of their tank. You will want to use many plants and rocks with this style and focus on materials that you could find in nature.

It also helps if you are familiar with the Rule of Thirds and the Golden Ratio. These design elements require splitting your tank up into nine sections using two vertical and horizontal lines. You can concentrate your decorations in different thirds of the tank to make it more natural looking. If you want to create focal points, you can place eye-catching items where the lines cross.

The Golden Ratio occurs often in nature, making it a suitable design scheme for aquariums. The ratio is considered to be the most aesthetically pleasing sides of a rectangle. Using these elements will bring the rest of your tank together and prevent it from looking chaotic. Nature Aquariums make use of plenty of focal points to make their designs appear natural.


The Iwagumi style is a modern take on aquarium decorating. It is challenging but looks stunning when complete. The style was created by aquarist Takashi Amano, representing the love for simplicity and beauty within Japanese culture, and it is very hard for beginners to replicate.

The challenge of this style is keeping your design simple. You want to create harmony using just a few well-placed stones, some plants, and a few species of fish. Small schooling fish add to the sense of peace through their movements. These species tend to be best suited for Iwagumi tanks:

  • Black neon tetra
  • Cardinal tetra
  • Firehead tetra
  • Glowlight tetra
  • Harlequin rasbora
  • Rummy nose tetra

These species are preferred because they move calmly through the water. In Iwagumi, you want to have at least ten fish in your school.

Dutch Aquarium

The Dutch Aquarium is the oldest planted tank style, as it became popular in the 30s and originated alongside the Dutch Society for Aquarists. What’s most interesting about this style is that it does not use driftwood or rocks, only plants, and comes with several rules you will need to follow.

The idea is that you are creating an underwater garden. While this might sound like the Nature style at first, the two look very different, as Dutch-style tanks are not scenes that you could find in nature. This style also requires a lot of maintenance in trimming plants.

You will need to choose where you want to place your plants carefully. Depth, perspective, focal points, and other design elements help to bring these tanks together. You also need to consider the colors and sizes of the plants you use.

Overall, there are three main concepts that your Dutch tank should follow:

  • No more than one plant species per four inches of tank length
  • No duplication of plant species in another group
  • A school of fish should be of at least 12 and all the same species

These rules make the style very restrictive, so many hobbyists come up with their take on the style. A tank will usually be Dutch if 70% or more of the tank’s bottom has plants covering it. Because of this, you will want to ensure your plants have access to a lot of nutrients in the substrate.

You Can Break the Rules!

Of course, your tank can look however you like by breaking the rules. You can take certain features and ideas from these styles, then change what you want. If you don’t want to follow a style, then don’t. You will have the most fun building your tank when you design it your way.

There are plenty of fun substrate options that don’t look natural. Neon gravel is one of the most popular options, as it can add a “pop” to any aquarium, so don’t be afraid to break the rules!

Start Building Your Aquarium

You are ready to start building your aquarium when you have all your tools and substrate, and you have an idea of how you want to arrange your tank. Many aquarists draw their plan on paper first. Then, make sure to wash all of your substrate and decor before you put them into your tank.

Keep in mind that you don’t have to build your entire aquarium set up in one go. Many fishkeepers take their time and adjust as they like until they feel their design is perfect. The rest of this article shows you what you need to do to build up your substrate.

Build the Base of Your Substrate

To build the base of your substrate, you can use cut pieces of styrofoam. This material provides a strong base, among several other benefits. The foundation of your substrate is essential because it needs to be strong to support the materials and the weight of the water above it.

Start with a few cuts of styrofoam on the bottom of your tank, making sure it doesn’t touch the walls of your tank. Are you wondering why you should add styrofoam? It comes with plenty of benefits:

  • Creates a more profound sense of depth within the tank
  • Saves a small amount of substrate material
  • Protects the bottom of the tank from scratches and chips
  • Provides a strong foundation

Styrofoam works very well in large, planted tanks because you can firmly plant any aquarium soil you use on top of the styrofoam. If you set it on the empty glass, the earth could easily slide over time.

However, styrofoam is a base that could float away if you don’t hold it down, so you need to make sure to add a lot of substrate and decorations on top of it. Stones, driftwood, slate, and other decors can hold the styrofoam in place.

How To Cut Your Styrofoam?

To cut your styrofoam, start by measuring the bottom of your tank. Then apply those measurements to your styrofoam and cut it with a utility knife. You want the pieces to be a few inches shorter than the tank all around. Take care in laying these pieces.

That way, the styrofoam does not touch the sides of your tank, which makes it invisible when the substrate is finished. You should also set the pieces in the center of the tank to raise your substrate’s center. A higher center gives your aquarium more depth and makes it even more interesting to look at.

Your cuts don’t need to be pretty because no one is going to see them!

Add Your Porous Material

Adding a porous material on top of your base allows nutrients to readily travel through it, and good bacteria to have a suitable environment to grow in. This layer also helps the later layers resist compaction as time goes on, so you want to choose it carefully.

You should apply the porous layer directly over top of the styrofoam because it helps raise the center of the tank further and holds down the base. You want to leave gaps between the styrofoam and the tank walls should be left clear, but you should still see some of the glass floors.

Many porous substrates contain plenty of nutrients. They may also include different materials, such as Fluval plant stratum, pumice, or lava rocks.

Importance of Porous Materials

The importance of porous materials to a tank substrate is that they allow water to naturally flow through them. When building your tank, you want to ensure that natural filtration can occur, since it provides many benefits. Without them, the tank’s environment would be less healthy.

These materials are good for plants, which help stabilize the environment for your fish. The porous substrate also allows good bacteria to grow, which then aids in the nitrate cycle.

The cycle starts with your fish because they create carbon dioxide, which your plants then use and filter out. Your fish also produce ammonia, which bacteria are responsible for filtering. From there, bacteria make nitrates, which can leave your tank in two ways:

  • The nitrates are removed naturally by plants
  • You remove the nitrates when you change the water

You will need to use both methods, even if you have a lot of plants because the build-up of these chemicals can be hazardous to your fish. To keep them healthy, you need to cycle the water in their tank at least once a month.

In short, your substrate creates a space for good bacteria to grow and aid the nitrate cycle so you don’t want to leave it out!

Add Your Additives Across the Base

You will want to add some quality additives across the base in your substrate to provide nutrients for plants and help condition the water in your tank. Substrates are important for healthy fish, so you don’t want to skip this step.

Next, place your additives on your foundation. Again, you want to put them on the pile you’re building and not the gaps where the tank’s bottom is exposed.

Start by spreading the additives across the base. You will want to use a spray bottle to moisten dusty materials, which keeps them secure and prevents the material from blowing around your tank.

Aquarium substrate additives contain plenty of nutrients that release slowly into your soil, where plants can absorb them. Additives also create an environment that boosts the growth of healthy bacteria and can benefit your fish by keeping the water parameters stable.

You can find additives that contain activated carbon, which provides additional clarity to your water. If you think your other substrate layers will make the water cloudy, carbon additives can be helpful to have in your tank.

Model the Foundation

Modeling the foundation of your substrate is the best place to start planning the rest of your design. You can make several adjustments and stop when everything feels “right”. As mentioned, some aquarists draw out their final design plans on paper, then model the foundation after it.

If you want to include aquascaping in your tank, then here is where you start. Use a tool, like a protractor, to begin modeling the substrate foundation and push the material to the sides to make gaps or paths, which you will later build on.

You should use the protractor to move the top layers of the substrate, including your sand and gravel. The flat end should be able to easily push the layers; many people build mountains and valleys with their material. You want thicker areas where you can set decorations, as well as open space for your fish to swim.

The foundation can appear however you like. You want to push the materials gently with your protractor, so they do not mix too much. This step is essential since it will determine how your tank looks later on. You may want to check out some samples of aquascaping for inspiration.

Place the Mesh

Many aquarists will also use mesh in their substrate because it is useful in building their substrate exactly how they want it. Plus, it allows the roots of plants to reach through to the lower levels. You should take some time placing the mesh layer for the best results.

Without mesh, the layers of your substrate will compact and mix, so you will need to add a mesh fabric layer to provide support and prevent mixing. This Zoo Med Terrarium Mesh works excellent at keeping your substrates separated.

The mesh should allow plants to spread their roots through the layer, where they can reach your foundation substrate. You will need to cut the net with scissors so it fits over the substrate properly.

Add the Sand and Soil

Sand and aquarium soil are some of the most popular tank substrates. They replicate a natural environment for your fish and are perfect for growing plants. Without them, your plants would have a harder time absorbing nutrients and staying connected to the tank. This is the layer you see the most.

Your next layer should include sand and soil or gravel. You will want to keep the substrates separated for now. To do this, you can use paper, cardboard, or other items to separate your materials, then lay down your “wall” and add the substrate on either side of it.

Add the sand and spread it out. You will want the sand layers to be higher towards the center and back since this adds more depth to your aquascape and it should come forward to cover the bare areas of the tank.

Finally, you can add the soil. Depending on what you are building, it should be level with your sand layers. The soil should be exposed to the surface so that your plants can take root there.

Decorate Your Aquarium

Decorating your aquarium is many fishkeeper’s favorite part of building a tank! You want to have several items of different sizes that are safe for your fish. Make sure that you wash everything before placing it in the tank. Then, you are ready to start decorating.

Once you have removed the walls keeping your top substrates separate, you can start adding your hardscape pieces, such as stones and driftwood. You can make your tank look however you want! Many people enjoy this stage the most.

You should use items of different sizes and try not to make everything look too uniform because, in nature, rocks and pieces of wood are never the same sizes. Once you have everything added, you will want to add more soil to hold your pieces in place.

You’ll want to add soil around the base of your decorations, then sprinkle some on top. With rocks and driftwood, it looks more natural to have dirt on them. You are done with this step when everything is how you want and feels stable.

While decorating, there are several factors to consider:

Your Tank’s Size

fish tank
The size of your tank will significantly impact how you decorate it. You want to make sure your fish have room to swim and feel comfortable. Smaller tanks have less room, so make sure you don’t take it all up with hardware. Your fish will appreciate some plants and open space too.

Too many large pieces can quickly crowd your tank and make it look too “busy,” which can cause your fish a lot of stress. Remember, “less is more.”

A few lovely decorations are going to look better than a crowded tank while giving your fish more room to move around. It might help you to choose a theme before you start decorating because it makes it much easier to include only needed accessories.

Create Zones in Your Tank

Creating zones in your tank as you decorate can help you visualize your final product. You want to take time to consider how the decorations look together and make each zone a bit different. Too much of the same can make your tank look “off” to others.

To give your tank a sense of balance, you will want to split it into three different zones: top, middle, and bottom.

Other fish like to hang out in these different zones, so none of them should be too crowded.

You will want to have a few items that enter the top zone and a few that stay in the bottom. This design element gives your fish more room to explore without feeling too exposed.

Think About the Color of Your Fish

The color of your fish can clash with your decorating scheme, but they can also complement it well. Most aquarists base their entire tank around the species of fish they add. You can try to do the same for the best results.

When decorating, make sure you consider the fish you are adding to the tank, as light-colored fish look best against a dark substrate, while bright fish look best with pale decor.

Place Focal Points Inside Your Tank

You will want to place one or two focal points inside of your tank, which should draw the eye towards them. You can achieve this by using items that stand out against the rest of the tank. It helps to think of these points as places where your tank “pops.” Place your favorite decor there.

To determine where the focal points should be, imagine two horizontal and two vertical lines going across your tank, which should split into nine even sections. Wherever the lines cross is a perfect place for a focal point.

You can set brightly colored plants in those areas, significant gaps of space, big rocks, or other decorations that stand out. The focal point should draw the eye to that space. You might want to put your favorite decorations there.

Don’t Add Sharp Edges

Never add sharp decorations to your tank. They can cause harm to your fish and may even lead to an infection. You should always inspect every item thoroughly before you add it to the aquarium. Not checking pieces could lead to something sharp being added.

Always check decorations for sharp edges, which are common on fake plants, as they can hurt fish and may cause an infection. You want to ensure you never add anything dangerous to a tank. If you don’t know what not to add to a fish tank, make sure to do some research before decorating.

Plastic and ceramic are not safe materials for your fish. If you are simply creating an aquascape without any fish, they might be alright to use. These items can leach toxins into the water, which can cause a lot of harm to animals.

Add Some Moisture to Your Substrate

To add some moisture to your substrate and decorations, use a spray bottle to cover them. This process helps you prepare for adding plants and also ensures your substrate sticks together. If you skip this step, you have the risk of a landslide when you add plants later.

You don’t need to soak your tank; just make sure everything is slightly moist.

Place Your Plants in the Aquarium

Placing plants in the aquarium makes it feel more natural and adds a lot of style. You will want to consider the needs of the plant, but also its appearance. That way, you can include it in the overall design of your tank. The plants will take root in your substrate, so remember the CEC levels.

Fish stores will often sell live plants to you in a pot. The roots will be kept safe in wool, which you should remove carefully so as not to damage the plants.

Next, you will want to add the plants to your aquarium. Make a small hole in the top substrate with your finger. Then, place the roots into that hole and cover it back up. You may need to use tweezers for smaller plants.

Add the large plants at the back and the smaller ones at the tank’s front. Doing so ensures that you can see into the aquarium easily. Plus, it looks nice!

You can place some plants on the hardscape you added before. To achieve this look, use dark brown thread to tie down your plants. For this to look natural, make sure you attach the plants by the bottom section.

Fill Your Tank With Water

how to build up aquarium substrate
You want to fill your tank with water so you don’t wash away all of the hard work you just did. There are several ways to do this, but the easiest is to add a plate to the bottom of your tank. It should prevent the water from destroying your aquascape.

Start by placing a small plate at the bottom of the tank and slowly pour your water on top. This process ensures that you don’t undo all of the hard aquascaping work you just completed by washing everything away.

Once you have it filled, you can turn on your heater and filter. Make sure to leave the electronics off until the tank is full.

When To Add in Your Fish?

Never add fish to your tank right away. You should always wait a week or two until the conditions of your aquarium have settled, because plants, decorations, and the substrate all impact the conditions of the water. Since you just finished, the numbers are going to jump around.

Unstable conditions can harm your fish. You should wait until the tank has stabilized and the pH conditions are suitable for fish. Once you have reached that stage, you can add them to your aquarium.

Before adding fish to a new tank, test the water thoroughly. Some specialty fish shops offer free water tests each month. However, you might prefer to do it yourself, as it is much easier to correct changes in your water if you catch them right away.

If you plan to start a tank, think about getting an aquarium pH test kit before setting it up. You can test however often you feel is needed.


Building your aquarium substrate is more straightforward than it might sound. You can create a wide variety of designs and make an environment that your fish will love. A lot of work goes into building the base since that is the foundation of your entire aquarium.

Once you start, it’s a lot of fun! Many people enjoy creating a world within their aquarium. There are several styles to consider, or you can make your own. Make sure to check out other posts for more details on substrates and aquascaping.