How to Buy Substrates for Your Aquarium? (Guide, Criteria, FAQs, Things to Look for & Avoid)

With so many different varieties of substrates out there, it’s difficult not to agree with us when we say it can be difficult to make a choice. 

Luckily for you, we’ve asked the experts and experiment on our own to bring you this guide on what to look for when buying substrates for your aquarium. 

In today’s post, we’ll help you figure out what type of substrate is ideal for you. 

Why is it Important to have Substrates in an Aquarium

The plants you have in your aquarium have a root system. This root system can be simple or complex depending on the plant. This root system is required for the plant’s nutrient intake and growth. On land, plants are rooted in soil but what are the plants in your aquarium rooted in? This is where substrates come in. 

Aquatic plants cannot hold onto glass surfaces and thus, require a rocky/gravelly surface for them to stick their roots into. It should go without saying that if you have a planted tank, some form of substrate is an absolute necessity. 

Plants aren’t the only thing that gain benefit from substrates in your aquarium. They also help keep fish feces and waste near the bottom of the tank and prevents it from floating around in the water making it dirty. The fish waste gets trapped in the substrate where it is eventually siphoned off by the fish tank filter.

Substrates also provide your tank with a natural look. Not only will your tank look aesthetically pleasing, your fish will be happy too as this will be much closer to their natural environment. In nature, the bottom of rivers, lakes and oceans are not bare, they are covered with natural materials such as sand, mud and pebbles. This is exactly what substrates are able to mimic perfectly.

What are the Different Types of Substrates for Aquariums? 

You’ll find that there are several varieties of substrates available in the market that fulfill different purposes. You can get a single substrate that is suitable for your needs or you could even try combining different varieties in order to achieve the best possible effect. The two main types of substrates are: 

Aquarium Gravel 

This is the most common and popular type of substrate because it’s easy-to-use and lacks complexity. It is ideal for most aquatic plants and fish. 

It’s different from gravel commonly found in the street in that it has smoother edges so it doesn’t harm your fish and will not move around easily. 

It comes in multiple shapes, sizes and colors so you have a lot of variety to choose from.

Aquarium Sand 

How to Buy Substrates for Your Aquarium (Guide, Criteria, Things to Look for & Avoid)

Sand is a common type of substrate that is used especially in beginner tanks. If you have fish that like to dig underneath the surface and bury themselves, you’ll definitely want to get this variety of substrate. However, we must warn you that aquarium sand is usually very fine and can get lodged in your filter if you have the kind of fish that like to stir up the sand a lot. 

How do I choose the best Substrate for my Planted Tank?

There are several factors that influence the effectiveness of substrates in your planted tank. The main factors you should be looking at are: 

Particle Size

The particle size of the substrate can impact the health of your fish as well as ease of cleaning. Substrates with smaller grain sizes are able to trap fish waste much better than substrates with larger grain sizes. 


The color of the substrate is merely there for aesthetic purposes. You can choose what color you like and get the appropriate substrate. However, you should look into how these substrates got that color. 

Some dyed substrates tend to “leak” their color into the tank water once they are placed inside the aquarium. This might not only cloud your water, it might also raise the pH levels. 

Reactivity with Water

As mentioned above, some substrates can raise the pH of your water. Usually these are substrates that are made from white dolomite and are high in calcium and magnesium. Some fish such as African Cichlids require alkaline conditions but if you have that want neutral or soft water, you might want to avoid substrates that can raise the pH levels of your water. 

Can a Single Type of Substrate be used for different types of Aquarium Plants? 

How to Buy Substrates for Your Aquarium? (Guide, Criteria, Things to Look for & Avoid)

Most aquarium plants work well with gravel which has a higher grain size. Aquarium plants tend to wrap their roots around them and position themselves firmly in the tank. 

However, you may require sand along with gravel if you have fish that like burying themselves. 

In this case, you might want to invest in both aquarium gravel and sand. You can try mixing these substrates with a layer of gravel underneath with sand on top. However, we must warn you that the aquarium sand will eventually sink to the bottom and you might have to top it off again after some time. 

How much Substrate do I need for my Planted Aquarium? 

There’s really no limit to this. You can use as much substrate as you like as long as your monitoring your water’s conditions to make sure the pH levels don’t rise or fall too drastically. 

As a general rule of thumb, you should never have a layer of substrate that is less deep than 1 inch. 

What kind of Texture should I be Looking for in a Substrate? 

A substrate that seems light and has a porous texture is generally preferred. You should also hold them in your hand and ensure that they are smoothed out with no rough edges as these could harm your fish. 

A porous texture allows the roots of your aquatic plants to wrap themselves around the substrate firmly and securely.

How can I Replace my old Substrate with a new one? 

The most efficient way of doing this is by using a pipe to siphon off the old substrate and then adding the new one. You’ll need a pipe that is generally thicker than the average pipe for a gravel cleaner. 

Once you’ve siphoned off all of the old substrate, you can add in the new one and top it off with dechlorinated water that matches the native temperature of your fish tank. 

The only drawback to this method is that there’s a possibility that you could suck out too much water when you’re siphoning off the old substrate. You may need to top the water up and then wait a few days before removing the rest of the old substrate as too much water change at once might be a source of stress for your fish.


Many people tend to put less focus when it comes to buying substrates for their aquariums but this should not be the case as they are essential in building the proper ecosystem within your fish tank.

We hope we were able to provide you with value and that your experience of shopping for substrates will be a lot less confusing now. 

Let us know what substrates you’re using for your aquarium.

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