Substrates and Planted Tanks

In the aquarium business and industry, substrate refers to materials that
make up the bottom of the tank. The purpose is to provide a kind of soil, or
soil substitute that promotes plant growth and beneficial bacteria that aid in
regulating your tank’s water cycle. Naturally, streambeds and shorelines of
rivers and estuaries are nutrient rich thanks to runoff buildup. Creating this
environment will allow these bacteria to culture and aid in breaking down,
recycling, and regulating ammonia, nitrites, nitrates, phosphates. This is
critical because this is small, closed environment without the natural
regulation. It is important also when choosing the right substrate because
certain plants and fish require more alkaline waters or acidic waters, are
more effective at feeding roots, and sequestering and breaking down
excessive nutrients.

First, we have to go with the planted tank. The Dustin’s dirt mix is for
experienced growers. Extremely messy set up, and requires regular
waterchanges for the first couple of days. With planted tanks, you’ll see the
most productive growth, hands down. Creates plenty micro and
macropores for the roots to take advantage of, offering the best medium
for gas exchange and nutrient storage. Cation Exchange Capacity (CEC) is the ability to absorb
positively charged nutrient ions. This means the substrate will hold
nutrients and make them available for the plant roots. It does not indicate
the amount of nutrients the substrate contains. This option would likely
have the highest CEC.

Similar to this, aquarists like peat substrates as well. These are usuallymade to mimic slow moving wetland rivers, like the Amazon! The name is derived from the leaching of tannins from decaying vegetation, making a consistency resembling tea. It is also valued because it is softer in texture, ideal for bottom dwellers. It acts as a natural ion exchanger, has a high CEC. Most importantly, for fish, it acts as a habitat for beneficial bacteria
that prevent algal growth, kill microorganisms that can cause harm to your fish or live aquarium plants by breaking down the organic waste that settles.

The most common tank substrate is straight gravel. Don’t choose sharp gravel if you have a fish, and none of that dyed crap. These gravels are often of quartz rich minerals, free of lime and limestone as these cause can cause the water to be much harder, and more alkaline. If you want alkaline, harder water, crushed coral or limestone would be your best possible substrate choices. They are often chosen for hard water species specifically, particularly cichlids. They’re also used commonly for saltwater tanks, and they’re great for inverts. Most mollusks require a
certain amount of calcium for their protective shells. Most stream and freshwater fish are adapted to more acidic, soft waters. Water that comesfrom lakes and rainwater is often devoid of the minerals that make the water hard.

Straight sand is often used as well, but only for certain species of fish. It
has a few advantages, being that it is a very soft substrate for bottom
dwellers to lay on and sift through for food. Many fish like to dig pits or
burrows. The smaller particles make it much easier for them to do this. This
also allows for a subtle, dune-like aesthetic to the substrate. It takes more
time for the sand to allow debris in than traditional gravel, but it is also more
difficult to clean after a longer period of time for the same reason if regular
maintenance isn’t managed. This can be avoided with filters, as the debris
will stay waterborne until it reaches the filter alternatively. Clay has a high
CEC, so it also frequently mixed with sand to provide available nutrients.
Some aquarists also enjoy putting different substrates in different parts of
the tank, experimenting with the balance of hard and soft substrates. Or
One side for a display, lighted area with gravel substrate, and the adjacent
‘forest’ substrate for your plants. I’ve actually done this, and made what I
call my ‘bonsai tank.’ I keep a small branch of manzanita driftwood that
looks like a small bonsai, and tie buce and anubias to it. I bury this in a
couple inches of gravel. I do this while keeping my tall, rooted plants on the
other side for a pleasing aesthetic. Even without the manzanita, it would
look like an underwater beach! Get creative with it!