Aquascape : Aquarium substrate

Another important part of the aquascape is the aquarium substrate. Aquarium plants use the aquarium substrate as an anchoring place and as a source of nutrients. Basically the aquarium substrate consists of:

In natural habitats such as lakes or rivers, substrates are actually warmer than water. To add warmth to the aquarium substrate and to provide water movements via convection currents, we need a substrate heating system. The substrate heater goes on the bottom of the tank under the aquarium gravel and provides a concentrated heat source through its coils. The water around the coils will heat up and rise, allowing cooler water to move down to the bottom - creating convection currents, also brings oxygen. Gentle circulations around the plants' roots increase the aquarium plants ability to absorb nutrients and preventing stagnant anaerobic spots. You should match your aquarium size with the capacity (wattage) of the aquarium substrate heater, more power (wattage) means a more/ longer coil to be put at the bottom.  

First (bottom) layer. It provides initial nutrients and will act to capture and hold nutrients brought down via the convection currents. It could be aquarium sand, aquarium gravel or nutrients-enriched aquarium substrate. If you use the nutrients-enriched aquarium substrate, the layer's depth can be about 2 cm only.

If you use either the aquarium sand or aquarium gravel as an aquarium substrate, you should initially fertilize them manually, just crush the aquarium fertilizer tabs and spread it over the first layer as a basic-fertilizer (see the dosage!), evenly mix the first layer and then you should cover it again with the remaining aquarium sand/ gravel. So, the layer should be thicker than the enriched one.

Top layer is more coarse than the bottom layer, it will seal in the bottom layer which contains aquarium fertilizer, and prevent aquarium water being polluted with the aquarium fertilizer. The minimum depth of the top layer is twice as the first layer.

Not all kinds of sand and gravel can be used for aquascape purpose. Some important considerations are:

• Limefree materials. Crushed-coral, sand or gravel from estuaries can't be used at all, they contain high calcium which will increase the pH and water hardness levels. The lime content will still there, no matter how you wash it.

• The grain size of the first (bottom) layer should be smaller than the top layer. That's why it would be better if you use aquarium sand or aquarium laterite, the denser materials can capture and hold nutrients much better. For the top layer, choose the porous aquarium gravel with 2-3 mm (1/16" to 1/18") in particle size. Avoid using sharp-pointed gravel that can hurt the plants' stems or bottom-feeder fishes (such as suckermouth catfish, botia, corydoras, etc.)

• Use a dark-coloured aquarium gravel. It's more for the sake of the fishes, your pet fishes are more comfortable with the dark substrate. Take a look at the color of the fishes, most of them have dark colors on their backs and light colors on their bellies. It's relating to the camouflage towards predators, dark-coloured backs will camouflage fishes with the substrate, whilst the light-coloured bellies will camouflage fishes with the bright sky.   

• The thickness of the aquarium substrate. Aquarium substrate should be thick enough for keeping the aquarium fertilizer in and for the roots' growing place. Some aquarium plants such as Anubias, Hygrophila or Rotala need moderate thickness (+ 6 cm), whilst some Echinodorus need deeper aquarium substrate (+ 10 cm) to anchor its long roots. Please check your aquarium plants' need first to plan the proper thickness of the aquarium substrate. 

Check out the next steps about preparing your aquascape project in our next articles.