We will address all questions regarding the base of all our aquariums in this article and take stock together on the substrate. Indeed, the ground is the first element that we will put in a newly installed aquarium. It is therefore completely legitimate to ask a whole host of questions about it such as: what type of substrate? How much should I put? Should I use substrate, nutrient or not? We will answer all these questions.

What is the substrate?

To begin with, it is important to explain the term substrate. The substrate is the substance that serves as the base for another layer. The soil substrate of an aquarium has two main roles: the first will be decorative and the second, much more important, will be to serve as a support for aquatic plants.

What are the types of substrates?

There are three types of substrate. There is the nutrient substrate, the classic soil substrate which we also call decorative soil. And finally, the so-called technical soil substrates that we have only been finding for a few years now in the aquarium industry.

So let's start by talking about nutritious soil.

Do we really need it? Can we do without it? In which cases to use it? When not to use it?

First, let's go back to what nutrient soil is. The only role of nutrient soil is to provide nutrients to your aquatic plants through their roots, often mistakenly called “aquarium soil”. However, aquarium nutrient substrate has nothing to do with garden soil.

The soil used in our gardens is not suitable for aquariums for several reasons. First, its composition is not at all adequate because it is mainly composted plant debris that will release several elements into the water that will modify the pH, add a lot of nitrogen and therefore a lot of nitrates. Also, it is something that will easily float in water which is therefore not at all suitable for an aquarium whereas the nutrient soil in our aquariums is more like sand which is mineral enriched and full of good nutrients.

For our plants, nutrient soil is not mandatory in every aquarium. You can do without unless you want a very well planted aquarium with plants like grass plants that are going to need nutrients and are very demanding.

On the other hand, if you just want to have an aquarium with easy plants, fast-growing stem plants like waterweed or kabamba, or if you want to have plants that grow on roots like java ferns or anubias, you can easily do without nutritious soil without any problems. This is because many plants get their nutrients through their leaves but not necessarily through their roots. Plants use roots mainly to stabilize themselves in one place, but not necessarily to feed themselves.

Regarding the thickness of nutrient soil to put in your aquarium, it is recommended to put between one and two centimeters maximum of nutrient soil. If you add more, you will promote the appearance of algae because nutrient soils for aquariums are really very loaded with nutrients and it should not be counterproductive.

So, if you decide to put nutrient soil in your aquarium, you should plan to put a lot of plants. Otherwise, the nutrients that will gradually escape will mainly benefit the algae and not necessarily the few plants that you would have put in.

Classic floor substrate

We can also call it decorative floor substrate or neutral floor substrate. these are small gravels of quartz or sand from the Loire, for example. This soil substrate will serve as a support for your plants as well as a first layer of decoration. However, be careful with quartz sand or gravel as it is a sharp substrate. So if you have burrowing fish like goldfish or corridor fish that will snoop around the ground and spend their time on the ground, they can damage their barbels.

So pay attention to the types of fish you have, quartz is not always ideal.

The good classic substrate remains Loire sand. It is the safe bet of all aquariums. It is important to know that any soil substrate, even neutral, such as Loire sand or quartz will harbor good bacteria between their grains which will help the aquarium to purify and filter itself naturally. Obviously, the greater the soil layer, the more effective this filtration will be, unlike nutrient soils.

It is very strongly recommended to always have a soil, whatever it is, in order to have a biological balance in your aquarium. Be careful, however, not to use anything and everything as aquarium soil substrate. For example, we cannot use coral sand for a freshwater aquarium. Indeed, coral sand consists of small crushed shells which will release limestone and the limestone will increase the hardness of your water, which is harmful for most freshwater aquariums.

Also pay attention to the sand that you can take from the seaside and which also contains a lot of small crushed shells and which will again increase the hardness of your water.

Another point, these small fluorescent pink, fluorescent yellow, red, green, etc. gravels are also to be avoided because they are artificial. And often these paints tend to release toxic elements into your aquarium water. So it may not be visible to the naked eye and it may not be visible to your fish's health right away, but in the long run it can cause health problems for them.

Technical floors

They have been around for quite a short time in the aquarium industry. We have been finding them for about 10 to 15 years, no more. These are floors that are not going to be neutral. They will alter the water chemistry of your aquarium by altering the pH, KH and sometimes GH. Technical floors are mainly used in two cases: aqua keeping and shrimp farming.

For aqua keeping, quite simply because a pH between six and seven is favorable to good plant growth. And for shrimps, this will lower the cache, sometimes to zero, which is very favorable for their breeding. These soils are of course artificial and all look alike. They look like small pellets and are often composed of peat, which helps lower the pH.

And for the rest, these are small, slightly sweet components that will be added to each composition. The best known of these technical floors is the ADA Aqua Single Amazonia which is widely used in the world of shipping and in the world of shrimp. Be careful, however, technical floors are not cheap. It takes 20 € for three liters.

Disadvantages of technical floors

The biggest disadvantage of technical soils is in particular that of being very light and therefore not very easy to plant. The plants will take a little time to take root and by the time they take root, they will often rise to the surface because the soil being very light, they do not have much support.

The second negative point for technical floors is that they will wear out over time. You're not going to be able to keep them for five or ten years. They will have to be changed after one, two or even three years.

How to choose your floor?

First of all, it will depend on the fish population you want to have and a little bit on the plants you want to have too.

First concrete example if you want to have an aquarium with African cichlids, it is useless to have nutritious soil since these fish constantly move the soil by making small mountains, hollows, valleys. So, it is really useless to have nutritious soil. In addition, these fish spend their time destroying practically all plants.

It will therefore be useless to have nutritious soil in this case. Same with goldfish. Most plants won't hold up since they love to eat and dig them up. And they, too, are very fond of digging in the ground and will constantly make nutritious soil dust by stirring up the soil. So it is recommended not to choose nutrient soil with goldfish.

On the other hand, if you want to have a classic aquarium, a community aquarium with a few plants and small fish, it is recommended to have a first layer of nutritious soil in your aquarium, followed by a layer of Loire sand, gravel …it doesn't matter a soil of your choice so that you can easily feed your plants, whatever they are.

This may also save you the overdose of liquid fertilizers that it is not always easy to dose when we start in a classic community aquarium with small fish.

If you want to have plants and your substrate is not only decorative, I recommend you have a substrate height of 4 to 5 cm.

In conclusion,

If you have chosen to have nutrient substrate, you can put 1 cm of nutrient substrate and 4 cm of decorative substrate. This will make it easier for you to plant your plants and they will have less tendency to rise to the surface.

As already explained above, you can also do without nutrient soil if you do not plan to have many plants or if you want to have plants that do not need to root in the ground or plants with stems such as kabamba, watermilfoil, things that will grow on their own, even without nutritious soil.

Now, if you want to start an aquarium for shrimps or an aqua keeping type aquarium with demanding plants such as grassy plants, technical soil is more recommended.

It's going to be expensive, but you'll get what you pay for, especially when it comes to shrimp. Some can only be maintained on technical floors. This will help you to have absolutely perfect water parameters for the shrimps or for the plants.

Also pay attention to nutritious soils which are often loaded with iron. Shrimp don't like it at all. So avoid having classic nutrient soil if you have shrimp.