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Sand Bed Question'¦Functionality --
Hi WWM crew!
It's been ages since I've required your advice, mostly because
I've been tankless for a good long while, but the 260 gallon system
that's going in to the wall of the house I'm building is
The sump and frame are installed, we're just waiting for the
display tank to be built.
My question for you is regarding sand beds. I know you guys advocate
deep sand beds,
<<Some do, yes'¦me included>>
but as I'm sure you're aware there are also very vocal schools
of thought out there that thinks they are unnecessary/problematic.
I have intentions of keeping wrasse fish species that require a sand
bed, so I fully intend to have one, but the specific mechanics of it
are yet to be determined.
First - here's my tank dimensions: viewable on two sides,
71.25 inches long
34 inches wide
27 inches tall
<<I do like the added depth, front to back>>
There will be two internal overflow boxes (unfortunately, couldn't
be avoided this time) on the long ends, and I plan on having three rock
islands, but a relatively open aquascape.
<<Mmm, yes'¦just recently revamped my own 96x30x30
in-wall display using the 'negative space'
It will be powered by 4 Vortech MP40s (or possibly 2 MP40s and 2 MP60s
if I can afford it) and a 5500gph return pump, so my tank should have
plenty of flow.
The sump is something of an unconventional custom design, in that
it's 26 inches tall, will hold approximately 100 gallons of water
when the return pump is running, and has one very large compartment
that can be isolated from the main water circuit for automated water
changes. There is no dedicated refugium chamber, but there is a 26 inch
long, by 8 inch wide, by 18 inch deep (18 inches of water depth that
is) chamber that I had initially planned to use as a frag chamber. So
the question becomes what I should do for my sand bed. In my original
plan, I was going to put a 2 inch layer of either CaribSea Aragamax
select or Fiji pink sand and be done with it. However I've been
reading more and more about the importance of sand beds, including your
primer on DSBs, and I now think 2 inches in this aquarium would be the
exact wrong depth.
<<Maybe'¦maybe not. I have seen some very nice systems
utilizing sand bed methodologies that seem to go against perceived
logic/standards. Things like stocking densities, feedings, substrate
grain size, et al aside'¦I think it just has much to do with
maintenance'¦or maybe more precisely, 'how much
maintenance' a hobbyist wants to take on>>
However, I don't want to go much shallower as that could be bad for
<<Yes'¦ 2-inches would be the minimum for any burrowing
wrasses'¦with many authors advocating twice this
but the other direction starts to send me towards a deep sand bed. In
my last aquarium (a standard 90), I had 2 inches of sand and after 1
year I had algae problems that simply could not be controlled. I'm
starting to think it's because I had a non-functional nutrient sink
of a sand-bed.
<<A possibility'¦but what were the contributing factors
to make it so>>
So I guess my questions are this:
1. Would you consider 4 inches of one of the above mentioned sands
(0.5-1.5 mm grain sizes) on a tank my size to be a 'deep sand
<<Re functionality, bacterial stratification? Yes'¦
Would a deeper bed perform better? Maybe so'¦ But we need also
to balance aesthetics here'¦what do you want to see when you
view the display?>>
2. If I were to forgo a deep sand bed and stick to 1 inch of sand or
less in the display,
<<Not recommended'¦if planning to keep burrowing
would it be worthwhile adding 6 inches of sand to my frag compartment
even though it's relatively small compared to the overall
<<It will provide 'some' benefit, even if only to provide
a 'refuge' for plankters to prosper'¦is worthwhile in
There will be less flow in that chamber, so I could probably get away
with sugar grained sand in there.
<<Is what 'I' would utilize>>
3. What are your thoughts on adding 3 inches of sugar sand to the
display tank, then covering it with an inch of courser grained sand
like the Fiji pink, or even special grade reef sand (1.0-2.0mm grain
<<You can do this, though it will 'mix' with
Would that still function as an effective DSB?
I'm trying to avoid sandstorms when the Vortechs kick in to full
<<Do research/consider setting these up to produce a Gyre-type
flow pattern. I utilize sugar-fine aragonite in my display, with Tunze
Stream pumps configured to produce a gyre-type flow
pattern'¦no problems with 'sandstorms' at
all'¦unlike previous configurations set to produce
random-chaotic flow. I'm not knocking random-chaotic (is used
by/useful to many folks), I just think gyre-type flow patterns are more
natural and very effective'¦regardless of your substrate
4. If I were to go the DSB route in the display, what are your thoughts
about burying rock in it?
<<Creating some type of stable base; as in burying rock, is
usually recommended/necessary'¦especially if stocking
My planned construction sequence will be to build the majority of my
rock structure (2/3 of total rock) out of dry Marco rock, place it in
the empty aquarium, fill the bottom of the tank with dead sand of
whatever grain size and depth I choose, fill the tank with R/O water,
add salt, cycle the tank using the shrimp method, then add the
remaining 1/3 of my rock as live rock that I'm ordering directly
from a wholesale distributor (the logic being that adding uncured live
rock to a pre-cycled Marco rock tank will minimize further die-off
during the curing process), then as a last step either add the 6 inch
layer of already 'live' sand to the frag chamber, or inoculate
the sand bed in the DT, or both.
<<Up to you'¦I would likely do
Thanks in advance and my apologies for the gigantic e-mail.
This tank is being built right in to the house and sits right in the
middle of the most visible, high traffic area of the house,
so I want to make sure I do this right.
<<You're on your way to doing so. Cheers'¦
Bare Bottom or Coarse Shallow Substrate for Coral-Only Nano
I'm setting up a 28-gallon NanoCube for coral only (plus a few
Nerites, Ceriths, and hermits for cleanup duty).
I have never tried coral before, so I am a total beginner at this.
<<If you haven't found it yet, have a look here and among the
links at the top of the page
I've read most of the substrate discussions here,
but the vast majority concern DSB,
which I don't want.
Also, fine aragonite is not possible, as I know from prior experience
that in this small tank my powerhead will shift it into sand dunes.
So I'm left with the choice of bare bottom (possibly carpeted with
star polyps, xenia, Zoanthids, which is appealing) or about 1/2 inch of
coarse (0.5 mm - 5 mm) aragonite. The aragonite will (I assume) support
valuable benthic organisms better than a bare bottom.
<<Yes'¦or at the least, likely a wider
'selection' of organisms>>
It will also provide a bit of buffering, though admittedly not as much
as fine grade. So... considering that I am a beginner and want to keep
this as simple and foolproof as possible, do you think I would be
better off with a bare bottom or the thin layer of coarse
<<For aesthetics I prefer a sand/gravel
substrate'¦though the bare-bottom does facilitate better
monitoring and removal of accumulated detritus. But I think you would
be fine 'either way.' The use of a very shallow substrate as
you describe will be easy enough to clean periodically as you would a
bare bottom'¦and with no fishes in the system (and the
subsequent possibility of overstocking), probably a moot point. I
suggest you make a decision based on 'your' sense of
aesthetics'¦what does 'Tim' want here?>>
<<Happy to share'¦ EricR>>
Re: Bare Bottom or Coarse Shallow Substrate for Coral-Only Nano --
Thanks for your prompt and thoughtful response!
The aragonite I've been looking at is black, which will make a
great background for well lit corals. So per your suggestion,
that's what I'll go with.
<<Excellent'¦ Do keep that black substrate well vacuumed
to keep it looking good as it will certainly 'show off' any
detritus as well.