Substrate
From RTAW Reefpedia
Contents |
Introduction
The substrate is the finer material that is placed on the bottom of a tank to provide a location for sand fauna to live in and improve the appearance of a tank.
Options
Bare Bottom
Basically leave the bottom of the tank bare, within nothing on there. Though some place a layer of a plastic, such as the material used to make plastic chopping boards. That rapidly covers in coralline algae.
Sand
See also deep sand bed. In the past, plenums have also been popular.
Suitable materials for use as a sand be are as follows, what is important is that the material used is either inert or calcerous, and of the appropriate particle size.
Calcerous Based
Using a calcium carbonate substrate (i.e. coral sand or crushed marble) can also have the added benefit of buffering alkalinity. However, this is not as effective as other methods of calcium/carbonate buffering, often taking longer times to contribute significantly to buffering capabilities.
Silica Sand
Silica sand, contrary to popular belief does not increase diatom blooms, see Silica Sand by Rob Toonen.
Gallery
Resources
- Beginner's Column: Substrate, Substrates, oh the dilemma! by Terry Siegel - Advanced Aquarist's Online Magazine
References
FAQ
Is it OK to use beach sand as the substrate in my aquarium?
The issue of contamination of the sand is potentially a concern. It wouldn't be considered that contamination should be enough to stop you from using it, but it should probably be rinsed prior to use - which would be a bugger of a job on 100kg, but something that is advisable for any substrate used in the aquarium.
Since it will have been fully dried it wouldn't be expected that you would have an issue with parasites coming in with the sand. Even if you had collected it from the beach yourself it would not be considered that introduction of parasites is likely to be a real issue. You introduce many more organisms (both good and bad) with live rock.
The issue of particle shape may or may not be a concern, depending on where it has come from. If taken from beach / dune deposits of natural sand, I would expect the grains to be just fine. All of the creatures living in the ocean seem to cope with it just fine. It wouldn't be considered to be any different to naturally collected coral sand substrates from that perspective.
If it is decomposed / crushed sandstone then that might be a different matter. But in terms of grain shape, I think you will find that crushed marble will be just as bad, if not worse, since it is freshly crushed, and hasn't been subjected to any natural weathering processes.
(Note that this is illegal to collect beach sand without a permit in most places, please check with the appropriate local authoritories)
Are silica based sands OK to use in my aquaria
One of the normal accusations pointed at silica sands is that they are reputed to lead to higher silicate concentration in the water, and increased level of diatom algae. This is pretty much just a myth. Silica sand is highly insoluble in seawater. By definition, sand is the portion of weathered rocks that has not been dissolved or washed away over the millenia. Silica sand beaches don't dissolve in nature, and they won't do so in your aquarium either.Even if they did, diatom algae are not really a nuisance algae. They are eaten by a great many organisms, and tend to disappear after the first few weeks of establishing a new aquarium anyway.
Will calcium carbonate sands assist my water chemistry?
A common reason people go for calcium carbonate substrates are that they are said to assist in buffering pH. This is another myth, since calcium carbonate is also nearly insoluble at the pH of seawater. If your calcium carbonate sand is dissolving to the point where it is impacting on water chemistry, then you will have a drastically low pH, and will have more concerns on your plate than what sort of sand you are using. Additionally, the bacterial biofilm that forms on the surface of the sand grains pretty much isolates the sand minerals from interacting with water chemistry anyway.
Anything else I should know?
The key criteria for aquarium substrate are:
- needs to be chemically inert in seawater.
- appropriate particle size to support sandbed fauna. Most people use substrate that is much too coarse.
- colour. This is purely for aesthetics. Marine organisms really couldn't care whether the sand is white, yellow or black.
