./Systems/laurence
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The main tank will be a 60g black-backed acrylic tank on a homemade stand.
We chose this size because (1) there is a significant price increase above
this size, and more importantly (2) we can't really afford to stock even
this one, let alone a larger one. One thing that will become rapidly
obvious is that nearly everything here is homemade, whether that is more
because we are broke or because we like to build things would be hard to
say.
The main tank will be acrylic both because it eliminates syphons and
because it is more earthquake safe. This is kinda important, since a
while after we got our current tank we held all 500 lbs. of it on the
rickety el-cheapo stand by hand while the ground did the rock and roll
trick (we live in Southern California, remember). Stupid, I know, but it
worked. That was a bit too unnerving for me to want to ever repeat it.
Following the time-honored tradition of fleeing from one extreme to the
other, we are building a stand that according to my father would hold up
a truck. If I'd designed it, I'd have thought he was joking, but since
he helped us with the initial carpentry I suspect he was serious. He
builds things like that. It extends out in front of the tank for
something like ten inches to provide more stability and to make room for
the stuff inside the stand. It also has a bumper bar to rest against the
wall behind it, for more stability. (We live in an apartment and can't
bolt it to the wall studs.) There is a cabinet between the stand and the
wall (the bar actually is behind this cabinet). I'll explain about this
cabinet in a bit.
The tank will be lit by the homemade hood which sits on our tank now.
Currently it houses two 250W MH bulbs and two 40W FL tubes. As per some
recent discussion and advice, we plan to modify the hood so we can run at
least two and perhaps four more FL tubes. Oh, there is also a regular
incandescent fixture in the hood for a moonlight bulb.
The tank will be drilled, of course. Since the only things on this tank
that will need a mechanical filter are the pumps, we need no prefilter
inside the tank itself. The drain can be a small arrangement near the
surface (which we haven't decided on yet). This leaves a little more
space inside the tank, and I'm becoming a stickler for the one-mechanical-
filter-only rule.
This tank drains into another tank below it, which we call the deep tank.
The stand is 36" high, so that there is plenty of room for it. It will be
custom constructed out of 1/2" plywood with an 1/8" acrylic liner, and
acrylic viewports cemented to the liner. I'm not sure on the capacity
yet, but I think it will work out to about 35g. It will be visible
through the front and right side of the stand, with the wood painted black
under the acrylic. It will be lit mostly or completely with actinic
lighting.
If it is not obvious already, this tank is supposed to simulate a deep
reef environment to complement the bright, shallow reef in the main tank.
The main tank will have a lot of wave surge and motion, but this tank will
have only the inlet from the main tank. If that is too much, we will Y
the drain so that only some of it goes into this tank. The water will
enter toward the back and the bottom will be angled a bit toward the front,
so that this tank also serves as a settling tank. We will probably
experiment with vacuuming this settling area frequently versus keeping the
deep tank well stocked with detritivores and allowing them to do most of
the work. I would prefer the latter if it can be done without
compromising the low nutrient levels we are aiming for.
The deep tank drains through a drilled bottom into the sump. No trickle
tower, but possibly some chambers for carbon and such, depending on what
we decide to use. There will be some type of automatic or semi-automatic
limewater addition apparatus in here, draining into the sump. I also will
put a small powerhead here if necessary to ensure that the sump does not
collect detritus. It will not be as convenient to clean as the deep tank,
and it is not supposed to be a settling tank.
There will be lots of stuff in the stand, so we have planned a crawlspace
for access, with its own light. I also intend to wire switches for all
the various appliances on the left side, so that all the wires are hidden
and easy to access inside the crawlspace (I will naturally have to
insulate them from casual contact). Everything in the stand will be wired
through a GFI socket inside. I have also considered wiring it with its
own separate breakers. That's probably not necessary, but I may do it
anyway.
The stand will be covered with oak veneer plywood waterproofed with
several coats of satin-finish polyurethane to match the existing hood.
The inside will be coated at least with polyurethane, and I am considering
sealing the floor with something even more durable like fiberglass resin
(I think epoxy is probably overkill here). The idea is that the floor
should hold a fair-sized spill completely inside with no leaking.
There will be two to three 6' x 6" (roughly, could be 7' in the end)
skimmers in a separate cabinet to the right of the stand. The skimmer
cabinet bolts to the side of the rear cabinet, so that the entire
assembly is stable. At this point, perhaps I should draw a diagram.
Padded bumper bar against the wall
/
_____________________
--------------------------------
| Back || Skimmer |
| Cabinet || Cabinet |
--------------------------------
| |
| Main Tank |
| |
---------------------
| |Deep Tank| <- Stand extends to the front of
--------------------- the main tank, deep tank inside
The deep tank is inside the stand rather than on it, and is in the part
of the stand which extends in front of the main tank. The top of this
part, the surface directly ahead of the main tank, lifts up for easy
access to the deep tank. Both tanks are held very securely in place;
the goal is for the whole setup to survive any earthquake which the
building can survive. the back cabinet extends to the floor behind the
main tank and is actually supported by the main tank rather than the
floor. The reason for this rather unusual feature is that the floor
here slopes badly near the walls everywhere in the apartment (yes, even
where we don't have the aquarium), and because leveling something with
more than four support points is just too annoying for words.
Back to the water flow. As I said, the one mechanical filter is the
prefilter for the pumps. We will probably end up needing more than one
pump, and they will share one large prefilter. Depending on how well
the nutrients are under control and how well the settling tank works,
this prefilter could be a fine sponge or coarse mesh.
>From the pumps the water flows through several different lines.
Probably the biggest portion of the water flows behind and under the
rocks. The tank will be drilled for these lines, to avoid ugly hoses
running down the back wall. The rocks will be on a pvc matrix, probably
drilled. Some of this water will flow through the chiller first, but I
don't think that the chiller is rated for as much water as the entire
matrix will need.
More of the water is diverted to the skimmers, which will be constructed
out of large pvc pipe rather than the acrylic tube which we used for the
skimmer we use now. Five feet of 6" acrylic cost me $50, what I will pay
for 20 feet of 6" pvc, and the pvc will be far tougher. The one
undesirable feature of pvc is that it is opaque (or mostly so), so we
can't see when the airstones need changing. I am considering cutting a
port on the sides which would be covered with a section of acrylic tube.
This lets me keep the strength of the pvc over most of the skimmer,
including the place where I don't trust 1/8" wall acrylic--at the point
that the inlet and outlet tubes feed through the wall.
As a side note, in the unlikely event that we decided to risk the use of
an algal scrubber for experimental purposes, it would go between the
main pumps and the skimmers. Since I think that algal scrubbers give
off both dissolved organic nutrients and free-floating algal cells
looking for a coral to attach to and kill, and since skimmers remove
both to a degree, placing the scrubber right before the skimmer should
minimize the effects on the reef.
>From the skimmers the water gravity feeds back into the main tank. This
is an unusual design, but we have found it to work well on tall skimmers
such as our present one. The advantages are that it lets us run the
skimmers on the system pump without re-skimming the water in the sump
over and over. The skimmer cabinet has a limited amount of extra space
for storage, particularly if we don't install the third skimmer.
The rest of the water goes to the refugia and dump stuff in the back
cabinet. The back cabinet is our solution to the problem of placing
refugia. I think that refugia should gravity feed to the main tank with
no pumps intervening, but there is nowhere in a conventional stand to
put them. The back cabinet extends up to about the height of the tank
plus hood (and our homemade hood is taller than usual). It is divided
in half up the center. The right half is accessible over the hood (very
inconvenient) or through the front when the hood is off the tank (this is
not quite so bad as it sounds, since the only thing which needs to be
uncoupled is the 24-pin power coupler which carries the various wires for
the lights and fans).
In the right half of the back cabinet, above the tank, we have room for
two or three small refugia tanks. One will probably be lit and one
dark. They will each have a few bits of live rock, and be left
undisturbed as much as possible. We may well also have a sizeable dump
bucket hidden up here. This should allow us to get some dump bucket
action without having the bucket over the tank in the way of the lights.
On the other hand, we could use a bucket over the tank to provide a less
brightly lit spot in the main tank.
The left side of the back cabinet will have small storage shelves
accessible from the left side of the stand. One of the real problems
we have with a reef in a small apartment is storing all the gadgets,
chemicals, and stuff which go with it. Top shelf or two will probably
have to hold the air pumps for the skimmers, but the rest is intended
to hold reef junk. Likewise, we'll probably tend to take the 5-gallon
water jugs we carry lab water in and hide them in the crawlspace.
I don't believe I mentioned the live rock arrangement yet. It will
essentially be a cross between a the usual rock wall against the back of
the tank and an Adey-style reef crest in the middle. I want to bring
the reef crest as close to the front as I can and still be able to clean
it, and to either side of the crest have the usual sloping wall
arrangement. The inputs would likely all be on one side of the crest,
and the overflows on the other. Ideally, there would be more wave
action on the ocean (input) side than on the lagoon (overflow) side. I
doubt I would go the extent of making an Adey-style wave-catcher, but
you never know.
I don't know for a fact that this arrangement is better or even feasible,
but it seemed worth the experiment. How the presence of the pvc matrix
will affect it, I'm not sure. However, the matrix is an important part
of the design, since the detritus which does collect is kept away from
the shallow reef and in the deep tank and refugia. This makes sense
to me, since natural reef crests don't have flat bottoms sitting nearby
to accumulate detritus. Much of it I would expect to be carried away.
One could argue that I should let it accumulate on the lower-energy
lagoon side of the crest, or at least not have the matrix on that side.
I don't know what I think of that idea, but at this point I'm prepared to
ignore it.
I think that this covers most of it. The light timers will be easily
accessible, so that we can run a simulated year by a combination of
photoperiod, temperature, and moonlight. I hope we can do the moon
rise/set times right as well as the intensities, but with manual
control following the calender would probably get a bit annoying. I
will look into computer control at some point (using one of those dirt-
cheap 286's or something), but I think that that is outside the scope
of the project at the moment. If I live so long and get as far as I've
outlined here, then I'll start thinking about automated lighting (and
probably other things).
Whew. That took a long time. Gasp, pant. I think I remembered just
about everything. I wonder if anyone will read down this far. If you
did, I salute your fortitude. Comments and suggestions are solicited,
of course. Not everything is cast in stone (but I think I would rather
die than start over on the main stand).
Dustin
The Krib
Marine/Reefs
The Krib