Aquarists sometimes wonder what they should put on the bottom of their aquariums.
Is there a benefit to having substrate that is super fine vs something more chunky?
What about no substrate at all?
We will take a look at these options and you can decide which works best for you.
At Tidal Gardens, we run a bunch of separate systems, some that feature substrate and others
that do not.
There is a pretty big difference between them, but there isn’t a one size fits all when
it comes to substrate.
Depending on what you are trying to accomplish with your tank one option might make sense
than another.
The large tank shown here is a bare bottom system…
mostly anyway.
The thing people like about a bare bottom tank is that they are inherently easier to
clean because detritus collects on the bottom of the tank and can be removed easily.
The problem with that is there is little room for neglect.
A bare bottom tank must be siphoned regularly to avoid unsightly piles of detritus from
forming.
This particular tank only has one tang and one fox face to graze on algae.
This pair poops so much it boggles the mind.
If left unsiphoned for two days the tank will form a pile the size of a large brain coral
in one corner.
So is bare bottom right for you?
Let’s see.
The first thing that comes to mind is its a great solution for hobbyists that want very
strong flow in their aquarium such as SPS-heavy tanks.
Bare bottom tanks avoid the risk of strong currents kicking up the substrate and creating
a sand storm.
The second benefit is if you can keep up with the maintenance, it’s possible to maintain
a laboratory clean system with practically a mirror finish on the bottom of the tank.
Aside from this aesthetic, long-term accumulation of detritus can cause older aquariums to break
down as their processing capacity is exceeded.
Regular removal of detritus goes a long way towards preventing this.
Let’s move on and talk about sand beds.
These days, most substrates are ground up aragonite, which is a crystalline form of
calcium carbonate.
There are three major benefits of a substrate like this.
First, it is aesthetically pleasing, or at the very least more natural than a bare bottom
tank.
Second, substrates are capable of biological waste processing.
Microfauna such as worms and copepods grow in the sand and do wonders for nutrient control.
In our bare bottom systems, we see huge accumulations of detritus that need to be taken out.
In our systems with crushed coral, the substrate hides the detritus and processes the waste.
We even have a system that never gets attention and it is flourishing.
The corals are growing on top of one another.
I would say that we haven’t siphoned the gravel or anything in close to two years.
That said, the capacity of the substrate isn’t infinite and one day a major reboot may be
necessary.
Lastly, the nature of aragonite helps buffer calcium and alkalinity levels to a small degree.
Over time, the substrate dissolves similar to reactor media in a calcium reactor and
releases calcium and carbonate ions back into the water.
So is this substrate good for what you are trying to do?
Let’s see.
Crushed coral as opposed to sand is great for aquarists that are looking for a more
natural aesthetic yet still want relatively strong flow in their aquariums.
The weight of crushed coral keeps the substrate from blowing around.
Second, some types of fish require a coarse substrate such as engineer gobies and jawfish.
Third, a more coarse substrate is better for snails.
I’ve seen some snails struggle to right themselves or even move across sand that is
too fine.
So when would a finer substrate be preferable?
I’ve found fine substrates a good fit for low flow systems such as refugiums with heavy
macro algae growth.
Due to the fineness of the sand, it actually helps keep the detritus on top of it unlike
larger grain aragonite substrates that trap it inside.
Fine sand also is good for sand sifting diamond gobies, and wrasses that burrow at night.
So to wrap things up, I hope this video gave you some things to think about when deciding
on the type of floor for your reef.
There are pros and cons of each type so which one is best is really going to depend on what
you are trying to do with your system.
In the comments below, let me know which you ended up choosing and why.
Until next time guys, happy reefing.