Why Freshwater Aquarium Substrate Is Important
A freshwater aquarium substrate is vital to ensuring that plants can establish themselves, fish feel at home and a beneficial biological environment is formed. This article covers the subject in more depth.
Dictionary definition of a substrate (Compact Oxford English):
- an underlying substance or layer
- the surface or material on or from which an organism lives, grows, or obtains its nourishment
- the substance on which an enzyme acts
- a material which provides the surface on which something is deposited or inscribed, for example the silicon wafer used to manufacture integrated circuits
Purposes for substrate:
A substrate has multiple purposes in a freshwater aquarium.
- It acts as a natural base for the fish as they would not find glass as a bottom material in their original wild habitat
- It can be a haven for bacteria involved in the natural nitrogen cycling process
- Plants use it to establish themselves in the tank
Substances used:
The main materials involved in freshwater aquarium substrates are sand and gravel. Of course coral sand should be deemed not suitable for freshwater aquariums due its light color causing glare issues and suspended particulates causing issues with the fishes gills leading to scratching.
Another substrate that is used in marine environments is limestone chips. Although this can be used in freshwater aquariums where there are special problems with hard water as this substance will act as a buffering agent and soften the water if required. (It will also increase the pH).
Gravel:
There are several types of aquarium gravel available with a range of grades (different particle sizes and shapes). There is normal aquarium gravel, colored gravels, black gravel and gravel that has not been sieved and graded.
The ungraded gravel looks more natural as it has a range of gravel sizes. The darker gravel is useful when you want to have a darker environment for your fish.
Things to consider:
Before choosing your substrate you need to consider the type of fish you are proposing to have and their behavior patterns because;
- Fish that dwell on the bottom could be injured by rough or sharp edged gravel stones
- Fish that like to dig frequently can be hurt by sharp gravel pieces
- Some fish feed and sift the substrate at the same time. Again sharp grains would not be a good idea
- Depending on how the fish will be fed, food particles can fall into crevices in larger grade gravel and cause pollution
- Some fish prefer soft water environments. If so, make sure the gravel does not contain limestone as it will harden the water
Note: A quick test for limestone in gravel: add some vinegar to a bit of gravel and see if it fizzes. If it does you have limestone in it.
Explanation: The vinegar (acetic acid) reacts with the limestone (Calcium Carbonate) to release carbon Dioxide and form Calcium Acetate and water; CaCO3 + 2CH3COOH -> CO2 + Ca(OOCCH3)2 + H2O
Sand:
The best sand to use is filtration sand, not sand used in the building trade as that will compact. Filtration sand will allow plants to establish themselves as it has round grains and water can move through it.
Although if your are using an undergravel filter then the fine sand is more likely to clog up your filter on a regular basis so more maintenance may be needed.
And if you want to create a sloping aquascape then it will be more difficult with this material. In this case you may well choose to combine both the filtration sand and gravel to create the effect.
Conclusion:
Freshwater aquarium substrates are an essential and integral part of setting up a freshwater aquarium. You need to think about what type of fish you are going to put in your tank before you decide on the sort of substrate you will use.
And do not forget. It is important that before use, all substrates (as well as anything else going into your aquarium – apart from the fish of course) must be washed repeatedly with hot water to clean it up.
[Top two Photos by JohnstonDJ, Specious respectively]
