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Not all aquariums are the same, but whether you’re caring for plants, fish, coral, or all three, you’ll need a good substrate!
There are hundreds of different kinds available to suit the specific needs of your tank, which is a bit overwhelming if you’re new to the trade.
Each substrate has a unique set of physical and chemical characteristics; a mixture that’s good for your fish might not be beneficial to your plants and vice versa.
Benefits of Using Substrate in Your Aquarium
There are several benefits of using substrate in your aquarium. Primarily they are:
- Making your fish comfy
- A glass aquarium is not the most familiar environment for a fish. Thus, adding substrate allows you to replicate a fish’s natural habitat as much as possible and make them happier!
- Growing Plants
- High quality substrates come packed with nutrients that help plants grow. They also provide a more stable platform for them as mentioned below.
- Preventing Pollution
- A good substrate will help you cut down on pollution by trapping food & fish waste at the bottom of the aquarium instead of letting it float around the top.
- Stabilizing Position
- Because plants have a hard time holding on to surfaces such as glass, substrate is a good way to help them out by providing a more stable platform to grown on.
Different Types of Aquarium Substrate
Substrate comes in several different variations, including:
- This is probably the most common type. Ideally it should have smooth edges that make it ideal for fish. It comes in different sizes and lots of colors which can help you make your aquarium unique.
- This one is self-explanatory. It’s a great choice for beginners because most fish like to dig around in it. It’s much easier to clean since waste and dirt land on top of it instead of inside larger grains.
- Crushed Coral & Aragonite
- Both of these can raise pH levels in your tank and can create a saltwater kind of atmosphere even in a freshwater tank. However, coral needs to be vacuumed frequently since it doesn’t hide dirt and waste well enough.
- This is often the largest type of substrate and matches the natural environment of a lot of fish.
- Other types include: Aquasoil, Laterite, Fluorite and EcoComplete.
Top 5 Aquarium Substrates
1. CaribSea Eco Complete Planted Black Aquarium Substrate
- Specially designed for freshwater tanks
- Ecologically balanced for healthy roots
- Comes pre-prepped for less mess
For the exotic plant lover, a perfectly proportionate substrate is imperative for strong and healthy growth. The CaribSea Eco substrate arrives presoaked and ready to dump straight into your aquarium. Containing elements such as iron, calcium, magnesium, sulfur, potassium, along with Heterotrophic bacteria to more efficiently dissolve bodily waste produced by your fish.
Reviews on this product also suggest that it helps to keep tanks cleaner and naturally reduces algae, resulting in less power usage from cycling.
Although it does take a little while to settle in your tank, after about an hour you should be able to see clearly through the glass of the aquarium. This substrate is the same kind that is naturally found in the islands of Hawaii, Bali and Costa Rica.
Consumers have mentioned that the CaribSea Eco has a higher alkalinity than others, so be sure to test your Ph regularly for the health of your fish.
2. Seachem Flourite Black
- Can be used in any aquarium environment
- Can be mixed with other gravel substrates
With a slightly different physical makeup than the CaribSea Eco, the Flourite Black by Seachem is made from clay pellets rather than loose material. While this substrate does appear to work as advertised, make sure you have a good filtration system and rinse the clay before placing it into your tank. Some aquarium enthusiasts have mentioned that the Flourite Black has clogged their system.
This substrate can be used in any environment, but because of the dark color it kicks up, it may be best to strictly stick to plants when using this mixture.
Overall, it appears to make plants happier, and doesn’t kick up too much of a cloud when things are moved around inside of your tank. Just keep in mind that the makeup is clay, and not black sand.
3. Fluval Plant and Shrimp Stratnum
- Made from volcanic soil
- Helps to balance the Ph level in your aquarium
- Can be used for both aquatic plants and shrimp
Helping to reduce the amount of bacteria in your tank, this loose soil is high in minerals and also happens to be incredibly useful for plants in addition to fish and shrimp. The material itself is loose and won’t clump up when wet like other options do.
The downside to the Fluval substrate is that it might only be good for adolescent or baby shrimp. Once they become adults, they won’t be able to burrow as easily to hide their food and use the dirt-like substrate as a safe place to take refuge. Eventually, you’ll need to add extra material to your aquarium or use a different kind altogether.
4. Mr. Aqua N-MAR-066 1L Fine Pet Habitat Water Plant Soil
- Specially formulated for aquatic plants
- Low Ph, more alkaline than acid
For a lighter substrate, Mr. Aqua seems to be the best of all five for a plant-only tank. Like other soil-based options, you’ll probably have a pretty large dust cloud at first. However, it should settle after an hour or two.
The only real issue with this substrate is that it comes in small bags, so you may have to spend a little more than you’d hoped to fill up the bottom of your aquarium. If you’re planning to grow coral and other forms of plant life, you’ll probably need a couple extra bags to ensure that they’re able to root properly. This substrate remains a Ph level of about 6.6 to 6.8 when used by itself, and because of this you shouldn’t have to change out your water as often as you normally would.
5. UP AQUA Sand for Aquatic Plants
- Rinsing for this substrate isn’t needed
- More cost-friendly when compared to amounts from other brands
Thanks to the heavy weight of this substrate, it won’t give off excessive dust and cloudiness like other soil-based options. This might be a plus for people who just want to pour it in and be done with it, however the dust cloud on loose soil serves a purpose. The UP AQUA substrate doesn’t break down as easily as others, and as it goes through the chemical process it changes from black to grayish purple color.
As far as caring for your plants go, once you bury your roots you can expect to strong, healthy growth within a few weeks. While it is meant to have higher alkaline levels than acidity, you may want to start off adding a little less than you’d initially intended and then check the Ph again after a few hours.
The one common complaint that has been consistent across the board regarding UP AQUA is that the packaging is poor. Several aquarium enthusiasts have complained that their bags arrived ripped or with product falling out. Check that yours is sealed properly before you open it so that it can be exchanged or returned in the event that you’ve lost money to due to excessive substrate leaking out of the bag.
What to Consider When Buying Aquarium Substrate
What Will You Keep in The Aquarium?
The first thing to consider when buying aquarium substrate is what kind of inhabitants your aquarium is going to hold. If you plan to contain plants in your aquarium, then you need to choose a substrate which will provide nutrients that are essential to their growth & health.
It is often suggested to keep such nutrients inside gravels and not the water column due to roots being the primary channel that plants use to obtain their minerals. Alongside this recommendation, it is good practice for a planted aquarium’s substrate to be double layered. The upper layer should contain gravel or sand to avoid wash-outs and the lower layer should contain nutrients.
If your aquarium is only going to be stocked with fish, then your substrate should permit bacteria that is beneficial to colonize the tank.
Your layer of substrate ought to be shallow to block particles of food from dropping into areas that are not as oxygenated. This can prevent toxic hydrogen sulfate from appearing.
Reef and marine aquariums need to have calcium and magnesium introduced in order to raise pH levels appropriately.
What Type of Water You Will Use?
Companies make various types of substrates to match the various types of ecosystems you can have in your tank. Be vary, you can’t use substrate that is made for freshwater environments in a tank using saltwater and vice versa.
So, be sure to do your due diligence when making a purchase to ensure you get the right substrate for the type of water you will be using.
How Much Substrate You Will Need in Your Tank?
You are going to need to consider the volume or capacity of your aquarium when deciding the right amount of substrate to put in.
To use an example, if your tank has a capacity of 55 gallons, then your layers of gravel should be around 2 inches deep. But keep in mind, if you also have plants in the tank, then you’ll want to add a 1-inch layer of nutrients under the gravel.
For even bigger aquariums, your gravel layer can be up to 3 inches deep.
What Particle Size Will You Need?
Substrate particles, (gravel for example), are usually made in two sizes: fine and large.
Gravel that is finer is designed to give your aquarium a natural look and to imitate a fish’s natural environment.
The downside to finer gravel is that in needs to be loosened up often as they tend to clump up and cause areas of the tank to have a lower amount of oxygen.
Gravels that are made larger typically come in a broader selection of colors which gives you more control over how you decorate the aquarium. They can even come in a glow-in-the-dark option which is often a cool aesthetic.
The downside to large gravel is that it will need to be cleaned much more often because fish food gets dropped into their large gaps and can potentially turn toxic over time.
What Color Particles Do You Want to Use?
You’ll have many different options when it comes to colors, so it’s mostly going to come up to personal preference and how you want your aquarium to be decorated.
However, you should consider against getting substrate that is plant colored, as the fish might bit on them. It is best to try and match your fish’s natural environment as much as you can.
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What Quality of Materials Do You Want?
Make sure to look for companies that build quality products and have good reviews. You want to look for gravel that is smooth and not too sharp so you d0n’t hurt your fish. If you can, test out the substrate by running your fingers through a sample of it.
Aquarium Substrate FAQ
What Is Aquarium Substrate?
Aquarium substrate is a material that you put at the bottom of your aquarium. Its purposes are both functional and decorative.
It can influence the health of your aquarium inhabitants, the chemistry of the water and your filtration alongside affecting the comfortability of your pets.
What is Substrate Used for?
Essentially, substrate exists naturally in wildlife and is used for aquariums to mimic that natural environment that your sea life need to survive.
It helps to balance the level of nitrogen in the water, which controls what kind of bacteria live there. While it’s easy to assume that all bacteria is harmful or responsible for algae growth, certain types are necessary in order for aquatic plants to be able to take root and survive during the younger stages.
Just like any other creature, fish also produce waste substances such as urine and excrement, which you obviously don’t want floating around at the very top of your take.
Substrate forces these bi-products to remain at the bottom of your tank, mixed in with the soil, sand, or rock, instead of moving freely. It’s unattractive, and your fish might confuse it for food.
Do I Need Substrate?
If you’re fairly new to caring for an aquarium or just started the hobby, keep in mind that you don’t actually need substrate, but it definitely helps!
It’s actually quite common for people to choose to leave their tanks complete bare at the bottom, just don’t expect to raise shrimp or exotic fish that need dark places to rest.
Alternatively, at least provide small housing or statues that give your pets some small resemblance to the substrate shelter they use for hiding food and protecting resources.
Some Fish Burrow
If you happen to be the proud owner of a bottom feeder, or plan to allow your fish to reproduce, substrate gives them a safe and comfortable place to do so.
When fish lay eggs in the wild, they look for a dark, hidden area that is protected from predators who may come along; remember the movie Finding Nemo?
The situation is exactly the same, Nemo’s siblings weren’t hidden well enough and unfortunately were eaten by a much larger, hungrier fish.
What is Substrate Made of?
You can find substrate in forms such as sand, pebbles, gravel, and soil. However, there are other kinds that further assist the production of the nitrogen cycle through a slow, physical breakdown when they come in contact with water.
These are usually used to support plant life, and are comprised of things like Aragonite, Peat and Vermiculite.
You don’t have to stick to one type, and in some cases it might even be a better idea to use multiple kinds or cycle through them. For ecosystems that are a bit more complex, you can layer your substrate as long as you know what you’re doing.
How Much Substrate Should I Use for My Aquarium?
The rule of thumb is usually: 1lb of substrate per 1 gallon if your goal is a 1-inch layer of substrate in a rectangular aquarium.
A good example combination for a 1-inch bed inside a 10×10 inch tank is 8lbs of wet sand and 6lbs of dry sand along with 5lbs of gravel.
How Do I Test Substrate?
Sometimes we end up purchasing accessories and necessities for our aquariums and find out after putting it inside the tank that we’ve made a mistake.
If you aren’t completely certain about the outcome of adding substrate to your tank, try using a smaller container filled with water. Let it sit for a few days and take note of how long it takes to settle and whether or not there’s any clumping.
Doing so will give you a good idea of how it will affect your filtration system, and the health of your tank overall.
How Do I Clean My Substrate Before I Add It to My Aquarium?
You want to put in clean substrate to keep your tank water from becoming cloudy. To achieve this you need to wash the gravels and sand properly. A good tip is to put it in a clean bucket and blast it with water from a pressure hose. Make sure to pour out the dirty water after every batch you wash.
How Do I Put in Substrate for My Planted Aquarium?
- Put down a firm foundation with a substrate full of minerals, after you rinse it (mentioned above).
- Install your heater and filter after you fill up the tank with dechlorinated water.
- If you want to adjust your pH levels, then use a water conditioner.
- Put in an optional plant lamp for improved growth of your vegetation.
- It is recommended to keep it in this state for about 2-3 weeks before you put in your plants and fish.
How Often Do I Need to Change My Aquarium Substrate?
This depends on which kind of substrate you have. If your substrate increases pH levels in the water, then it should be changed every couple of months or few years. Clay substrates can be changed every 3-4yrs. Plant based substrates need more frequent changing and sand and gravel typically don’t need to be changed.
How Can I Keep My Substrate Clean?
How Do I Choose the Right Aquarium Substrate?
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Stock Photos from BLUR LIFE 1975 / Shutterstock