Pet Forum / Aquaria / Marine Reef / July 2005

"Mark Cooper" <vikubz@yahoo.com> wrote in message

Hi Mark,

You might find the following two part article from Advanced Aquarist Online
Magazine to be of interest:
http://www.advancedaquarist.com/2005/6/aafeature  (part 1)
http://www.advancedaquarist.com/2005/7/aafeature  (part 2)

The short version is that Toonen & Wee found the following:

1. That there is very little difference in the denitrification abilities of
various types of sand beds.

2. That shallow sand beds seem to be somewhat better able to process
phosphate.

3. That fine sediments are much better at processing phosphate.

4. That there is a small but significant improvement in animal mortality
associated with deep beds.

I think that it's important to keep in mind that these experiments were
intended to document only the water processing abilities of various types of
sandbeds. Further, the tests were done over a short period of time and with
a very restricted group of animals. I mention this, not to cast aspersions
on Toonen & Wee's very valuable experiment, but to point out that it doesn't
address many of the arguments in favor of deep beds that you would find in
Ron Shimek's articles.

As I see it, the trade-off is one of aesthetics versus utility. Many people
might find a 4 inch layer of sand to be interesting to look at but very few
would find such a thing attractive. OTOH: Depending on what sort of display
animals you have and on how much management you are willing to do, a deep
bed can, in and of itself, address some things that would otherwise be left
to the aquarist. Further, most of these management issues would be handled
better by the (presumed) complexity of a deep bed.

My own interest is in keeping cold water animals that are native to my area.
For that application, a deep bed is just about mandatory since a very high
proportion of the animals to be shown are filter-feeders that will depend,
to varying degrees, on the microfauna produced by the bed. Further, a goodly
number of our animals (including three species of really pretty anemones)
prefer to be partially buried in sand and some of the most effective
scavengers like to spend their 'down time' buried in sand.

I'm sure that you'll get a wide variety of responses to your post and that
many of them will directly conflict with each other. The thing to remember
is that every aquarium is different in a bewildering number of ways and
that, as such, every aquarium has different needs in terms of management.
Some mixes of animals will make a deep bed virtually mandatory but in many
cases an aquarium with the proper mix of animals will do fine with a shallow
sand bed of whatever degree of coarseness/fineness is convenient.

My personal opinion (and it's only an opinion) is that you can't go wrong
with a deep bed as described by Shimek. You may not absolutely need such a
bed but, like the chicken soup argument, 'It couldn't hurt!' OTOH: If you go
with a shallow bed there may be animals that either don't do well or that
require more effort on your part than you can afford to give. I think SPS
corals are an example of this but, as mentioned above, I'm a cold water guy
so I could very well be wrong.

Sedimentally yours,

TPG