The substrate in your aquarium

In an aquarium, the substrate is not only there to enhance the tank’s appearance – it also gives the plants somewhere to put down roots and creates a natural environment for your fish.

When setting up a new tank, the substrate plays an important role. After all, it needs to give your plants enough stability and create an environment in which your fish feel at home.
To put down the ideal “underlay”, we recommend the following basic approach: First of all, install a heating cable on the floor of the aquarium. On top of this you can add the first layer of nutrients (substrate) and then add a layer of coarse or fine gravel (the correct grain size will depend on which fish you are going to keep in the aquarium). However, you should only use this layer if your aquarium will not contain any fish that like to dig down through the substrate. Quartz gravel or quartz sand is particularly popular for the top layer.

The classic choice: pure quartz gravel
There are lots of good reasons for using quartz gravel. It’s loose enough to ensure optimal water circulation. It is also fine enough that it doesn’t have any coarse cracks where faeces and waste food could otherwise collect and transform into harmful hydrogen sulphide. Good water and oxygen permeability is also important to allow oxygen-loving bacteria to form on the tank floor. These bacteria process some of the nutrients that then contribute to healthy plant growth.

And that’s not all… with quartz gravel, an aquarium owner can let his imagination run wild when setting up the tank. He can use it to create special focal points as it comes in a range of different colours that can also be mixed together. Our tip: If you want your fish and plants to look their best, use warm, dark colours for the base substrate so that the colours of your greenery and fish stand out even more.

Quartz sand or quartz gravel as an alternative

When it comes to the diameter of the stones, there is a wide selection to choose from. As a rule, the faster the water flows within the habitat, the larger the size of grain you can use. This also helps to support good root formation for larger plants. You will also need to give some thought to the types of fish that will live in your tank. If you have bottom feeding fish, you will definitely need to choose rounded gravel so that your pets don’t injure themselves on any sharp edges. Once you have found the right kind of quartz gravel, you should rinse it thoroughly in cold water before putting it into the tank.
As an alternative to quartz gravel, you could use quartz sand, which is also available in a variety of colours. It’s perfect for fish that like to burrow and is pretty much a must for most types of catfish and angelfish. That said, using sand will theoretically limit the selection of plants you can use, as not all plants will find enough stability in such a loose substrate. You can counterbalance this potential drawback by adding larger stones around the plants to protect them.

If you use quartz sand, you will need to make sure there is enough ventilation. That will happen automatically when the fish sift through it and loosen it up. Burrowing catfish and loaches are industrious little helpers for this process, as are soil-dwelling snails. A light ground current will prevent sinking mulm from building up and will transport it to the filter. It’s important to note that if you are using quartz sand, you won’t necessarily have to place fertiliser underneath. That being the case however, you will need to add liquid mineral fertiliser additives with trace elements, particularly iron.

The right amount is important
For plant aquariums, we recommend a minimum height of approximately 2 cm for the nutrient solution. Then add a 6-8 cm layer of quartz gravel or sand. Any less than this and the plants won’t have enough room to develop their roots. You can also use this knowledge to create the ideal underwater world by building up the substrate at the back of the tank so that those plants have more soil. The plants along the back will then grow faster than those at the front, achieving a balanced look.


Practical tip You can check the purity of quartz sand by putting a sample into a glass of water. Wait until the sand has sunk to the bottom of the glass. If the water stays clear then you have pure quartz sand which you can use in your aquarium. Before you add it to the tank, however, you should still wash it thoroughly under cold water.

Call into your local store today to discuss your fish’s personal needs with our Maxi Zoo Pet Experts