Last updated: 25 Jun 2020

The Best Aquarium Substrate (Review) in 2020

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Olivia Williams
Published 09:17 am

We humans have gone far from our roots of nature where we used to dive in and marvel at the scenic beauty underwater. Nowadays, the only way we can access that pleasure is through small glass boxes which hold aquatic plants and animals inside clear blue water. Aquariums not only add a soothing aesthetic value to our abode but also encourage affection for animals and nature in the young family members.

However, taking care of these aquariums and decorating them need regular supervision. Since the substrate is one of the first things which go into the aquarium, selecting it is an important step. To make the process easier for you, here are ten of the best aquarium substrates as picked by our substrates.

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The Best Aquarium Substrate


Carib Sea has been making various products to enhance closed systems like aquariums for almost 50 years. It has gained high reliability from customers in this time period which is evident from the popularity of this aquarium substrate. It comes in a package of 20 pounds and is black in color.

This substrate is meant for aquariums with freshwater plants. This planted aquarium substrate contains a special formula which promotes root development for those plants. You might have seen how big and beautiful the vegetative bodies of Hawaii, Costa Rica and Bali grow. The rich chemical composition of that same oil resulting from the basaltic volcano is the main component here. It has more than 25 nourishing elements including iron, calcium, sulfur, potassium, and magnesium.

Thus, regular use of this substrate in your aquarium will make the plants grow lush and gorgeous. Since it is already so rich in iron, the water will not need any addition of laterite. It is also free from artificial color and coatings.

The highly porous spherical grains included here will ensure the right level of diffusion. On the other hand, its live heterotrophic bacteria will transform the fish waste faster into nutritious natural food for the plants. The inclusion of this substrate in the aquarium ecosystem encourages better balance ultimately making its cycling safer.

Rich in Iron and other minerals

 Highly porous spherical grains

 Contains heterotrophic bacteria

 For freshwater plants

  • Brand: Carib Sea
  • Model: 770
  • Weight: 20 lbs


Owned and operated by “hobbyists”, Seachem has remained one of the most admirable pet care companies with a unique vision. They continue their roots of sound science by bringing the fruits of knowledge derived from their chemists and biologists in every product!

Their Flourish line also comes from those scientific origins. This Excel substrate is also meant for the freshwater aquarium like the first one. It can offer a rich mixture of significant nutrients including microelements and trace elements. These contain iron, calcium, and magnesium among other substances which are highly beneficial to plant growth.

You can use it confidently on the invertebrate inhabitants of aquarium like shrimp. The combination of all elements is carried out carefully here preventing any kind of overdose for those precious lives. It, in fact, reduces iron promoting its ferrous state instead of ferric, which can be more efficiently used by plants. Most importantly, Flourish Excel functions as the source of simpler organic carbon which is readily available.

This planted tank substrate stops algae growth inside the system without affecting the aquatic livestock. It can be found in three sizes of 100ml, 250ml, and 500ml making it easier for you to make the most appropriate choice.

Three sizes

 Organic carbon

 Encourages ferrous iron

 No phosphate or nitrate

 Balanced mixture

  • Brand: Seachem
  • Model: 67104530
  • Weight: 1 lb


Another great aquarium substrate of Carib Sea is this one from their Super Natural collection. Although it is mainly meant for freshwater systems, it can also be used in saltwater aquariums since the pH level here is completely neutral. It is neither acidic nor alkaline making it a great option for all aquarium lovers.

The beautiful white color of this fish tank sand adds a stunning contrast to the whole aura in the closed glass tank. The nice and heavy sand also carries some shine making the enclosed aquatic world sparkle every now and then. Hence, this substrate makes your aquarium both aesthetically pleasing and rich in quality.

Its smooth grains are safe for the marine creatures with a soft belly. Also, being free of any artificial dyes and paints, this is one of the safest substrates you can get for your valuable collection of aquatic pets. It is available in five pounds, but you can settle for more than one pack if you want a deeper layer in the aquarium.

Natural white color

pH neutral

Both saltwater and freshwater

Soft-belly safe

Free of dyes and paints

  • Brand: Carib Sea
  • Model: 1 lb
  • Weight: 008479058201


The Seachem Flourish line also offers the rich mixture in tablet forms. One pack of these contains 10 tablets in total. One of these tablets inserted into the aquarium gravel bed will accelerate healthy growth for its plants. Each pack can treat a plant bed twice if it is about 12 by 30 inches in size. Since they are inserted directly into the bed, plants benefit from the fertilization faster, through their roots on tabs.

Every tablet is packed with a balanced combination of trace elements, vitamins, and amino acids. Among the trace elements, there are iron, calcium, potassium, magnesium, manganese, biotin, inositol and choline B12 involved here. All of these components will make the plants grow healthier.

Algae formation is decelerated by regular use of this substrate since it does not contain any phosphate or nitrate. These tabs need to be spread evenly throughout the gravel bed by pushing one in every 4 to 6 inches. New tablets must be introduced every three to four months to ensure optimum plant growth.

Although they generally do not affect the pH level, it can exhibit slightly acidic properties in soft or unbuffered water. These tabs are available in two varieties of the original version and limited version.

Gravel bed supplement

Targets plant growth

Essential trace elements

Vitamins and amino acids

No phosphate or nitrate

  • Brand: Seachem
  • Model: 67105050
  • Weight: 1.12 oz


For more than 35 years, Fluval has kept up its reputation in manufacturing high-quality aquatic products. This aquarium substrate meant for healthy growth of plant life and shrimps is one of their highly appreciated products on the market. It can be found in three sizes of 4.4 pounds, 8.8 pounds, and 17.6 pounds.

This fish tank substrate is made out of the rich soil from the foothills of Mount Aso Volcano located in Japan. As a result, it contains all the essential minerals including macro and micronutrients. This aquarium soil is ideal for freshwater aquariums since it exhibits slightly acidic properties.

For the same reason, it can be incredibly helpful for tropical aquatic lives. The newborn shrimps can arm themselves because of this substrate. They can keep escaping predators by taking refuge in this healthy stratum until they grow big enough to emerge.

When it comes to plants, the substrate promotes strong plant growth since the roots can easily procure all embedded nutrients by penetration. Besides, its light porous structure will allow beneficial nitrifying bacteria groups to colonize improving the water quality for plants. It does not discolor water. Instead, this substrate helps to keep organic discoloration resulting from natural driftwood in control.

Three sizes

Rich volcanic soil

Promotes plant growth

Porous structure

Neutral to mildly acidic

Controls discoloration

For freshwater use

  • Brand: Fluval
  • Model: 12693
  • Weight: 4.4 lbs


The renowned patented brand of GloFish specializes in genetic technology which transforms ordinary fish into fluorescent ones! That is why their fish tank gravel comes in six stunning vibrant colors which can glow in the dark if you want!

These bright shades include pink, green and blue in basic and fluorescent variations. Addition of such neon-ish colors will make any aquarium come to life, even in darkness! The substrate can also be of solid black and white frost colors for those who crave simplicity in their interior. So no matter what your aesthetic sense prefers, all of them can be satisfied with the GloFish range of substrate colors.

They use a proprietary formula to support such technology without harming the health of any inhabitant of your aquarium. It is available only in packs of five pounds. These gravels are not uniform in size which elevates the natural vibes of your aquarium.

Multiple vibrant colors

Proprietary formula

Responsible use of genetic technology

  • Brand: GloFish
  • Model: 29087
  • Weight: 5 lbs


One more time we welcome Carib Sea to our list of best aquarium substrates. This time it is one of their Ocean Direct products which incorporate the unique sea breathe technology. Carib Sea was the first one to come up with this idea which preserves real sand and its original bacteria.

Unlike most other substrates, this one brings all natural elements into your well-nourished aquarium. That is evident in each Ocean Direct packet containing bacteria which are up to 100 times more beneficial compared to other preservation methods.

Each grain in this packet is encapsulated by capillary action and coated by a thin film of actual ocean water. This thin film ensures an unparalleled level of gas exchange with the atmosphere, eliminating any chance of accumulating metabolic byproducts.

It is available in two variations named original grade and oolite. The original one offers a density of 96 pounds per cubic foot and oolite allows 87 pounds per cubic foot density. Choose the one that best suits your aquarium style and structure.

Sea breathe technology

Original bacteria preserved

Unparalleled gas exchange

  • Brand: Carib Sea
  • Model: 008479009401
  • Weight: 4.3 lbs


This regular aquarium substrate developed by Spectrastone is one of the most affordable options on the market. It is ideal for freshwater aquariums although it will not affect the pH level of water.

This substrate consists of gravels of varying sizes which range from about 5mm to some large pieces close to 10mm. They do not have any artificial color on them and look pretty natural. So if you are on a budget and are looking for a simple solution to your aquarium substrate, this will be the one to go for.

Even though it is meant for aquarium use only, you can also spread it out around roots of succulent plants. Along with increasing their aesthetic value, the gravels can also promote better growth for those plants. It contains a non-toxic coating and mixing it with water does not make the environment cloudy.

Does not affect pH level

Non-toxic coating

For freshwater

  • Brand: Spectrastone
  • Model: 5 lbs
  • Weight: 11509


Make way for another Seachem product which mainly consists of sand and gravel. This Fluorite edition consists of carefully fracted and stable clay gravels which have a porous structure. Hence, this black aquarium gravel is ideal for tanks with natural plants.

It works the best when used alone as a single integral bed inside the aquarium. Although, if you are craving some more aesthetic mix-and-match, feel free to throw in some gravels from another category! Any modifier or enhancer like laterite is not required for Fluorite to function properly.

This substrate will not alter the water’s pH level so theoretically, it is safe to use in both freshwater and saltwater. There is no chemical coating applied on these gravels which boosts their nutrition quotient even more. Along with making the plant root structures healthier, it ensures a long life for these plants.

Even though it comes pre-washed, it is better to rinse the gravels before use to remove any dust formed during transit. If you settle for the smaller sized Fluorite Black bag weighing at 3.5kg, you can rinse the substance in the bag with its specialized mesh bottom.

Two sizes

Specially fracted

Does not need laterite

Not chemically coated

No pH alteration

  • Brand: Seachem
  • Model: 67137250
  • Weight: 14.9 lbs


Nature’s Ocean has proved its capability by providing premium aquarium products since 1979. Keeping up the legacy, this high-quality live sand developed by them also offers a number of premium features. Its grains are pretty compact in size measuring just 0.1mm to 0.5mm.

The live Aragonite sand is obtained from nature and its natural goodness is preserved even in the packaged state. It can eliminate all nitrogenous waste including ammonia, nitrite etc. as soon as it enters the system. Using this will also guarantee instant ammonia cycling and enhance the buffering capacity. The proper level of pH is maintained by its regular use.

All you have to do is put it in the aquarium box, add saltwater and introduce the aquatic creatures. This sand can be used anywhere in the saltwater aquarium except under gravel filters. It comes in natural white color and in a pack of 10 pounds.

Removes nitrogenous waste

Instant ammonia cycling

Balances pH properly

Enhances buffering capacity

  • Brand: Nature’s Ocean
  • Model: 20731
  • Weight: 10 lbs

Best Aquarium Substrate Buying Guide

Things to Consider When Buying Aquarium Substrate

  • Type of aquarium inhabitants

Firstly, you need to ask yourself, “Who are the inhabitants of your aquarium abode?” If it contains plants, you should choose a substrate that provides the essential nutrients for their healthy growth. It is recommended to include those nutrients inside the gravels instead of the water column since roots are the main medium for plants to obtain those minerals. The substrate of a planted aquarium should have two layers - a lower one full of nutrition and an upper one of regular gravel or sand to prevent wash-out.

If the aquarium is full of fish only, the substrate must allow colonization of beneficial bacteria. The substrate layer should be shallow enough to prevent the food particles from sinking into a less oxygenated area since that can eventually result in toxic hydrogen sulfate. For marine and reef aquariums, you should introduce enough calcium and magnesium to raise the pH level high enough.

  • Type of water

There are different substrates available for different kinds of ecosystems. The one made for freshwater environments cannot be used in the saltwater environments. So check through the information of the substrate you selected to determine what kind of water it is made for.

  • Required amount

The right amount of substrate to put into the aquarium depends on its capacity or volume. For example, if a fish tank has 55 gallons capacity, its gravel layers should be about 2 inches deep. If there are plants involved too, a nutrient-rich layer of 1 inch can be added underneath the gravel layer. For bigger aquariums, the gravel layer can grow up to 3 inches.

  • Particle size

Gravels and other particles of substrates are mainly available in two sizes - fine and large. The finer gravel is meant to bring in the natural aesthetics to your aquarium and imitate the natural habitat for the fish. Larger gravels, on the other hand, are found in a wider variety of colors, giving you the option of playing more with the decoration. Some of them even glow in the dark making the whole setup much more fun than usual.

Larger gravel substrates will need more frequent cleaning since the unconsumed fish food deposited in their large gaps can turn toxic after a while. The finer gravels, on the other hand, need to be loosen up more often because they tend to compress together creating tank areas with the trivial amount of oxygen.

  • Color

When it comes to colors, you can choose among many but make sure none of them has actual paint colors on them. The paints can be nibbled on by the fish and cause it pain. If you want to take the safest road, choose the natural looking gravels which is the most comfortable for these fish.

  • Quality

The gravel quality should be smooth enough and without any sharp edges which can hurt the fish. So before settling on a substrate, run your hands on its sample and figure out if they feel smooth enough or not.

  • Water reactivity

The amount of required pH level in a tank varies depending on its residents. Certain fish species like African cichlids would require a higher pH level than usual. So aquariums with this type of aquatic creatures will need a substrate that buffers water like crushed coral. In contrast, species like angelfish need a lower pH level and thus substrate like peat moss is used in the system.

Aquarium Fancy Habitants

Benefits of Substrate in Aquarium

  • Plant growth

Most of the substrates are rich in nutrients which are beneficial for plants. They also improve the overall environment of the tank.

  • Stable position

It is hard for plants to hold onto the glass surface of the aquarium. So this substrate provides them with a better and more stable platform to stand on.

  • Pollution prevention

Substrate prevents pollution by keeping the fish waste and food waste at the bottom instead of floating around in the water.

  • Fish comfort

A glass surface would not feel familiar to the fish. Instead, a substrate layer mimics the natural habitat for them raising their comfort level.

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Types of Aquarium Substrate

  • Sand

Sand is the best substrate for a beginner since all fish love to dig and bury it. This makes cleaning much easier since dirt particles land on its top instead of getting lost in the grains.

  • Gravel

Aquarium gravel has smooth edges and thus make a comfortable substrate for fish lives. They come in varying size and colors to customize the tank’s appearance.

  • Crushed Coral and Aragonite

They both raise pH level in the aquarium and can bring the saltwater vibes to a freshwater environment. Crushed coral needs frequent vacuuming since its light color cannot hide dirt and debris very well.

  • Others

The planted tanks may utilize Fluorite, Laterite, EcoComplete, Aquasoil and similar substrates for nutrition and nourishment.

Best Aquarium Substrate FAQ:

Q: What is aquarium substrate?

A: An aquarium substrate is simply the substance placed at the bottom of an aquarium for both aesthetic and functional purposes. It has the power to influence the filtration, water chemistry, and health of inhabitants. A substrate can also affect the comfort level of aquatic creatures living in the tank by its color and texture.

Q: How much substrate should I use for my aquarium?

A: Typically, about 1 pound of the substrate is needed per gallon if you wish to form a one-inch bed in the rectangular aquarium. Also, 5 pounds of gravel, 6 pounds of dry sand and 8 pounds of wet sand are an ideal combination to form a one-inch substrate bed inside a 10x10 inches tank.

Q: How to set up substrate for a planted aquarium?

A: Firstly, lay down a strong sustainable foundation with a mineral-rich substrate after rinsing it. Then install filter and heater after filling up the tank with dechlorinated water. If you wish to adjust the pH level, use a water conditioner. Add a plant lamp for better growth of the aquatic vegetation. Keep it this way for 2 to 3 weeks before introducing plants and fish here.

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Q: How should I clean my substrate before I add it to my tank?

A: To prevent the tank water from getting cloudy, wash the dusty gravels or sand thoroughly. Put a small amount of the substrate in a clean bucket and spray water through a hose. Pour out the dirty water every time you are done washing a batch.

Q: How can I keep my substrate clean?

A: First of all, unplug all electrical components included like heater, filter, and pump. However, there is no need to displace the fish, plants and other decorations of the tank. Pick your cleaning tool of choice - a thick aquarium siphon for larger tanks or a plastic flexible tube for smaller ones. Put a bucket below the tank to hold in the old water. Submerge one end of the vacuum inside the aquarium while placing the other end in the bucket. Use your thumb to stop the water flow whenever necessary. After getting rid of all the dirty water, read the tank’s temperature and make sure the new water matches this temperature to not alert the fish.

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Q: How often should I change aquarium substrate?

A: Substrates which increase the pH level in water should be changed every few months to a couple of years. Clay substrates like Aquasoil need to be changed every 3 to 4 years. Gravels and sand don’t need to be changed since they are almost neutral. The plant-based substrates will need frequent changes to ensure proper nutrition and nourishment.

Q: How deep should my silver sand be?

A: If your tank has live plants, the depth of silver sand should be from 1 inch to 1.5 inches. If there is no live plant, it can go below 1 inch. A layer deeper than 2 inches can cause a build-up of toxic anaerobic bacteria.

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Q: Can I use a mixture of grain sizes?

A: A mixture of different sized grains can be used if you want a natural or colorful look in the aquarium.

Our Top Pick

According to our research, Carib Sea Eco Complete Planted Black Aquarium Substrate has turned out to be the best aquarium substrate. This freshwater black substrate has a highly porous structure and is rich in the essential minerals. It encourages strong plant growth by providing them with nutrients through roots and also converts fish waste faster into plant food using the heterotrophic bacteria.

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