I. Introduction to Refugia
What is a refugium?
A refugium is a body of water, separate from the main tank,
which shares a water source with the main tank. It is not
unlike a sump; however, the very definition of "refugium"
implies that it is used as an area of shelter.
Why add a refugium?
I first became interested in the idea of adding a refugium
to my seahorse tank because of a successful freshwater tank
that I had planted. I noticed that water in the freshwater
tank was always crystal clear and that the tank required very
little maintenance. It seemed to me that using plants in an
aquarium created a nice, circular kind of ecosystem that could
enhance the water quality for my seahorses.
A refugium can provide a number of benefits to your tank:
1. It can provide an area of shelter for fauna and flora
that would otherwise become food for the inhabitants of
your main tank. Copepods, amphipods, Mysid shrimp and other
critters can reproduce without predation. If you build an
overhead refugium with a gravity return, some of the critters
will eventually flow to the main tank and provide an additional
food source for your seahorses.
2. It can provide a place to grow macroalgaes to export
nutrients from your main tank. Caulerpa and other macroalgaes
consume ammonia/nitrates and phosphates that accumulate
due to overstocking or overfeeding. Placing these in your
refugium will allow them to grow without predation by
3. If can assist in maintaining pH levels. If you run
your refugium on a reverse photoperiod from your main tank,
you won't get the pH fluctuations that occur during the
4. It can be used for equipment that you don't want hanging
from your display tank such as a UV sterilizer.
5. It can increase your water volume.
The way you design your refugium is largely dependent on
what you wish to accomplish with it.
I built my refugium to achieve many of these goals, and more. My seahorse tank is, by any measure, overstocked. I wanted
the filtration benefits I'd read about. I was also increasing
my herd size significantly and wanted to increase the water
volume without buying a new tank. In addition, I wanted the
refugium to provide a place to raise fry where there would
be a large population of copepods and other critters, and
which would share a water source with their birthing tank. The reverse photoperiod would eliminate pH fluctuation that
may be detrimental to fry survival rates.
II. A Primer on Plumbing:
The concept of plumbing was probably the most difficult
aspect of the refugium for me to understand. If you are lucky
enough to have purchased a pre-drilled tank, you probably
have no difficulty understanding how it works. I didn't get
it. I did recognize, from reading the online aquatic message
boards, that preventing spills was a major consideration in
plumbing tanks. I eventually spent weeks poring over articles,
looking at various pieces of equipment and diagrams before
I really understood the concept. If you are unfamiliar with
aquarium plumbing, don't expect to understand all of these
concepts as you read along. I'd suggest reading this section
first from beginning to end, as it is difficult to comprehend
the purpose of the various parts until you see how it all
So you know that the water must go up to the refugium and
back down to the main tank, but how?
There are three essential parts of the plumbed aquarium system:
1. The overflow
2. The pump
3. The lines (pipe and fittings)
I first thought that I'd need two pumps — one to pump
up and the other down. Wrong. It is virtually impossible to
equalize the flow of water through the system, plus you run
the chance that one or both pumps will fail and you end up
overflowing one tank or the other. You avoid this by using
one pump to go up and an overflow to go back down, making
the flow down dependent on the amount of water being pumped
The overflow system is the same thing used to plumb a tank
and a sump; however, a sump is generally placed below the
main tank, while a refugium is above it. Here's a nice schematic
to show you how the overflow system works: http://www.sasala.com/fish/ref/overflow/overflow.html. As you look at the drawings, imagine the top tank as a small
refugium and the bottom tank as the larger display tank. It
works the same but the tank sizes are reversed from those
There are two ways to get water back down to your tank via
gravity. One type of overflow uses a hang-on box, and the
other requires a drilled tank.
consists of two acrylic boxes. One hangs inside the highest
of your two plumbed tanks, and has slots for water to flow
into it while (hopefully) keeping fish and other critters
out. It also has a box that hangs on the outside of the
tank, which is attached to a hose going down to the lower
tank. Water moves from the inside box to the outside box
by use of a clear acrylic "U-tube." Siphon keeps
the water flowing from the inside-tank box to the outside-tank
box. If the siphon breaks (e.g., algae or a snail gets in
the u-tube), you have a real mess on your hands. Water will
stop draining from the top tank to the bottom tank. At the
same time, your pump will continue to pump water from lower
tank up, possibly emptying the lower tank and overflowing
the higher tank onto the floor and burning itself out in
the process when it runs dry.
That said, a lot of people use hang-on overflows without
incident. CPR and Tide pool both make overflow boxes worth
looking at if you aren't into DIY and you don't want to
drill your tank.
of a small corner of the higher tank being sectioned off
using a watertight acrylic box. Inside the box is one or
more standpipes, mounted in holes drilled in the bottom
of the tank. Water flows from the main chamber of the tank
into the overflow chamber and then down the standpipe into
the lower tank. (The All-Glass Aquarium site has a nice
demonstration of how their overflows work:
It's a pretty nifty design but if you don't buy a tank
with built-in overflows, you'll have to get the tank drilled
to build it yourself. Drilling a tank is expensive, if you
can find someone to do it at all. And it requires that you
decide where to place the overflow-it must be positioned
high enough that water only flows down at a certain level. If the water gets below this level (as in the case of your
pump losing power and not sending water up to the highest
tank), it stops draining down to the lower tank. If you
place your return too low on the higher tank you may end
up draining it completely. It's not rocket science though,
and a little common sense goes a long way. In my opinion,
a drilled overflow is definitely the best way to go.
Selecting a Pump:
Generally, your refugium needn't have too much water flow.
I think 2-3 times the volume of the main tank is sufficient
(e.g., if you have a 30-gallon tank, you'll want a pump that
can handle 60–100 gallons per hour). You can't, however,
just look at the rating on the pump to determine which one
to buy, because these rates assume that the pump is taking
from and returning water to the same source. If the water
has to travel through a pipe, up and around a corner, flow
rates will be reduced.
Movement of water from a main source through pipes or tubes
is called "head." Some pump companies publish stats
of what their pumps will deliver at 0 head. There is a big
difference between this and what that same pump will deliver
at the head it will have to deal with in your system. The
distance that the water must travel up is called lift, and
this distance reduces flow rates considerably. Another consideration
is friction-unless you can pump straight up to your refugium,
there will generally have to be elbows in your pipe, which
further affect the stated GPH. A rough rule of thumb is that
any 45-degree elbow will equal one foot of extra head, and
a 90-degree elbow two feet. Total head will equal lift plus
friction through any elbows. Unless you understand these concepts,
the published flow rates can be very misleading. Flying Fish
Express has a good chart to determine the flow rates of different
pumps at a given head: http://ffexpress.com/drygoods/powerheads.htm.
In choosing a pump, you must also consider the size of your
overflow. Most pre-drilled overflows are rated in terms of
the GPH that they will handle. It is important to choose a
pump that matches the capacity of your overflow. This is not
as important if you build your own overflow because you can
then determine your return rate by the size of the standpipe
or the number of holes you drill in it.
You also need to decide whether the pump should be a submersible
(sit in the water) or an external (sits outside the tank). Submersible pumps are cheaper, quieter, and easier to install,
but may add heat to the water.
Okay, you have chosen a pump and an overflow method. All
that's left to do is run the plumbing from the refugium to
the main tank, and from the tank up to the refugium.
You can use clear vinyl tubing for this and it probably works
fine, but I like PVC. PVC and fittings are like tinker toys
for fish geeks.
PVC is poly-vinyl chloride pipe-a common plastic pipe used
for cold water distribution in plumbing. PVC is available
at any local hardware store and is easy to work with —
it can be cut and snapped using a cheap hacksaw. You cut the
lengths you need and then connect them with various fittings. Although it is not particularly attractive (white with stamped
printing), it quickly becomes encrusted with coralline algae. For some reason, coralline really likes to grow on some synthetic
substances. PVC pipe is also cheap — less than $2 for
an 8' length.
PVC pipe comes in various diameters. For most aquarium purposes,
you can use either 1/2" or 3/4" (or larger, if you
have a very large aquarium). Your PVC, bulkhead and fittings
should all be the same size. "Fittings" are plastic
pieces in various shapes that you can use to curve ("U"s,
"L"s), split ("T"s) or just connect the
The most important fitting for aquarium purposes is the bulkhead. You probably won't have a lot of luck finding bulkheads at
your local hardware store, but many fish stores do carry them,
or you can buy them online. A bulkhead is a three-part fitting
that resembles a large nut and bolt with a hole in the
centre. The third and most crucial part is a rubber washer that fits
in the centre. The bulkhead is set inside the hole so that
the washer and nut are both on the outside of the tank. By
setting the bulkhead this way the rubber washer is only minimally
exposed to saltwater. As a result the saltwater does not dry
and shrink the washer as quickly as would occur if the washer
were constantly submerged. The bulkhead should fit snugly
within the hole in the aquarium wall with there not being
more than a 1/8-inch gap between the bulkhead and the edge
of the hole. The closer the two fit the less likely there
is to be any leakage. If this gap is too large it can be filled
in with silicone rubber. This should be allowed to dry completely
before it is exposed to any water.
Because of the relative difficulty of finding bulkheads,
you may wish to buy them first, and then buy the PVC and fittings
later. Right now, I have systems using 1/2" and 3/4"
bulkheads. If in question, err on the size of caution by buying
pipe big enough to carry more water than your pump could possibly
send through the system.
Regardless whether you use clear tubing or PVC, you'll need
to measure the distances between the tanks. Also, because
your PVC may have to make a few twists and turns to get from
one tank to the other, it's a good idea to draw a scaled blueprint
of your plumbing system and, before you begin, make sure you
have the right fittings. Cut the PVC to the proper lengths
using a hacksaw and then, before gluing the pieces of pipe
and fittings, put together the entire system to make certain
the pieces properly connect your tanks together. If it works,
pull the pieces apart and glue them. They should be allowed
to dry for 24-48 hours to allow the glue to cure completely. Please note that after applying glue and placing the pieces
together they will set in a few seconds. Make sure you glue
the right pieces together in the right position.
Be careful when choosing glue. I always use aquarium sealant. Some silicone is ammonia cured (obviously a no-no in our tanks)
but aquarium silicone is vinegar cured. I have heard that
it's okay to use plumber's glue but I have not tried it.
Finally, if you have a UV unit, you can plumb it between
the tanks to utilize the same pump or return. You just treat
the UV unit like a piece of PVC pipe that the water must pass
through. Incorporating a UV sterilizer may make your plumbing
design slightly more complex but make your overall system
look a little cleaner and less like a science project.
Overflow connection: If you are using a hang-on overflow
box, you may prefer using flexible tubing. Just slip the
tube over the barbed fitting on your overflow, and secure
with a hose clamp. With a drilled overflow, PVC should be
glued securely into the bottom of the bulkhead.
At the tank end, you have a choice to make. Either let
the tubing just hang into the tank compartment, or drill
a hole in the side of the tank and install another bulkhead
fitting. (Obviously, with a glass tank, you may have to
just let the gravity-return line hang into the tank. ) Secure
it in some way (tie straps, cord) so it can't flop out and
spill water on your floor. If using PVC, you can use elbows
to curve the pipe as necessary and drain as deeply into
the tank as you like. My PVC goes all the way to the bottom
of the main tank, ensuring some water flow in the nethermost
regions of the tank.
Pump line connection: Connecting the plumbing to the pump
will vary on the pump design. Many pumps have some sort
of barbed fitting on top. You may have to use a fitting
called an "enlarging coupling." For instance,
my Rio has a 3/8" fitting, but my PVC is 3/4".
I have the Rio fitting inside a piece of flexible tubing
that is glued inside the PVC. I'm sure there's a better
fitting to use but this is the best I've found.
III. Building the Refugium
As I stated earlier, I liked the idea of the refugium after
seeing what wonderful results I had achieved with a freshwater
planted tank. I had also recently purchased a few mated pairs
of seahorses and I thought a refugium might make a good nursery
tank for several reasons. With 14 horses in my main tank,
I was slowly seeing a rise in nitrates, no matter how many
water changes I did. I hoped that the macroalgaes would perform
a denitrifying function. I wanted to maintain pH over the
24-hour cycle, I wanted a place where copepods could reproduce
for the fry, and I liked the idea that the fry would have
good water quality (both due to the presence of the macroalgaes
and the larger total volume of water). I had a few other design
elements in mind that would make it "fry friendly."
After the plumbing, deciding how to place the tank was the
most difficult item to figure out. I wanted the refugium to
sit over the main tank and I did not want to obstruct the
view of the main tank. I definitely did not want to break
down or move the main tank. I needed something I could just
slip over it. The design I had in mind looked a little like
those units that sit on four legs over a toilet. The problem
was building something that would withstand the weight of
the refugium and be stable enough not to fall over (since
there wouldn't be a shelf near the bottom to brace the legs).
I looked at building such a unit but finally decided that
my woodworking skills (and available tools) weren't yet at
the point that I felt comfortable trying it.
I finally went into a store called Organized Living that
sells modular metal units. You buy the legs and shelves in
the sizes you choose and put them together to create a unique
unit that serves your purposes. The 12"x36" shelves
are supposed to hold up to 350 pounds, and are made of an
open mesh design that was spaced enough to fit the PVC through
it. I bought two shelves. I placed one just high enough above
the main tank to allow the hood to open completely. The second
shelf sits at the top of the unit's 74" legs, just above
where the refugium would be. (The top shelf serves little
purpose except to brace the unit. ) I also purchased additional
braces to connect the legs at the bottom and sides for stability. I was already using one of these units for my entertainment
centre so a matching shelf looked good in my living room. It was an attractive, albeit expensive, solution to my problem.
As with a sump, there are no set rules as to what size your
refugium should be. Some places sell in-tank refugium that
are probably less than a gallon in volume; you could conceivably
have a refugium that was ten times the volume of your main
tank. The things to keep in mind are the weight capacity of
the stand you are using, how much pump you can afford and
the amount you want to spend on lighting-remember, the larger
the tank, the more light you will require.
My first attempt at a refugium used a 20-gallon glass tank. I couldn't find anyone to drill it for a reasonable price
(I was quoted a price of $40 per hole with no guarantee against
breakage). I first made a DIY overflow box. I know that these
boxes can work fine but I wasn't comfortable with it, largely
because I recognized the likelihood that fry would get sucked
into it. It also required too much clearance in the back of
the tank and just didn't look neat. Possible overflow due
to loss of siphon was of particularly concern in a refugium
full of macroalgaes — one stray piece in the overflow box could
I finally decided to change the refugium to an old ten-gallon
acrylic tank I had and that I was able to drill myself.
I purchased two 3/4" bulkheads from my local LFS. I
wanted the bulkheads on the bottom of the refugium, on either
end. I'll describe more about the design later but, basically,
one hole was for water to flow in and the other one was for
the overflow down to the main tank.
I didn't have a routing attachment on my drill so, instead,
I drew a 7/8" circle on the acrylic and drilled a bunch
of tiny holes along the line. I then just punched out the
hole where the bulkhead would be fitted and glued.
My overflow. Most overflow chambers utilize a design whereby
the water flows from the top of the main water chamber into
the overflow chamber, from where it drains down to the main
tank. In this way, tiny critters in the main chamber of the
refugium would eventually make it down to the main tank. Because
I hoped to use my tank as a rearing tank, I wanted to avoid
the possibility of tiny fry getting sucked into the overflow.
My overflow chamber makes up about 1/4 the volume of the
refugium. I built the chamber by cutting two pieces of Plexiglas
to make the chamber walls. Each piece is the width of the
refugium tank, and about two-thirds the height. Using silicone
sealant, I attached one piece from the top of the aquarium
going down, about 4" from the end wall (leaving 3.5"
clearance on the bottom). I placed the second piece of Plexiglas
parallel to the first wall and about an inch from it (away
from the tank wall), but from the bottom up (clearance at
the top). Between the two pieces of Plexiglas, I placed a
sponge to prevent the fry and critters from flowing through
to the overflow chamber.
(See diagram. )
The overflow's standpipe is a piece of PVC that sits in the
middle of the overflow chamber and runs from the bulkhead
up to the height of the refugium (11"). I drilled a bunch
of holes in the top of the standpipe to just below where I
expected the minimum water level to be. This way, if the pump
shuts down, water will never drain from below the level of
the drilled holes in the standpipe.
Because I knew that one of the challenges of raising reidi
and/or OR fry is to prevent them from sticking to the surface
of the water and sides of the tank, I wanted to incorporate
a surface spray bar into the water pump line. I did this by
sizing PVC and connections to fit inside the perimeter of
the main refugium chamber (approximately 14"X 10"). The four pieces of PVC are connected using 90-degree elbows
in the corners. To make it work like a spray bar, I drilled
1/8" holes approximately one inch apart along the entire
length of the PVC. When I put the pieces together, these holes
were situated to spray out against the tank walls, creating
surface turbulence (to prevent fry from sticking and also
for air/gas exchange). I then placed a solid piece of PVC
at the end of the tank, upright from the bulkhead to the top
of the tank wall, and attached my spraybar using a "T"
joint. Water comes up through the bulkhead, rises up the PVC
and, on reaching the top of the tank, is disseminated around
the entire inside of the tank walls at the water surface by
means of the spray bar.
(See diagram. )
Connections and the UV Unit:
Time for plumbing! I diagrammed the two systems to figure
out where my plumbing lines should be. There were a couple
of things I had to take into consideration: the size and shape
of my existing hood and the size of the pump I wanted to use. I have an Eclipse 3 hood on my main tank and I wanted to be
able to use the existing openings on either end. These openings
were, however, farther apart than the length of the 10-gallon
and I didn't want to cut any extra holes into the Eclipse. This meant that I would have to include some elbows in the
design, as well as both vertical and horizontal PVC (because
the water couldn't run straight up to and straight down from
the refugium into the existing openings in the Eclipse hood). As for the second consideration, I had an extra Rio 800 but
the flow rate was a little higher than I wanted through the
refugium. I decided to include the elbows in the line up (remember,
increased head decreases water flow) and then have the gravity
return perfectly vertical.
The pump sits in the far back left corner near the surface
of the main tank. I connected it using a fitting called an
enlarging coupler (the fitting in the Rio is 1/2" and
my PVC was 3/4"). I used a 90 degree elbow to go up the
tank and through the back of it, a 1" piece of PVC and
another 90 degree elbow to reach the refugium (approximately
6") and another 90" elbow to reach up to the bulkhead. With approximately 5 feet of head, the Rio is rated at 100
GPH (at 0 head, its rating is 211 GPH). The plumbing looks
something like this:
(See diagram. )
The overflow design was much simpler. Initially the PVC went
straight down from the bulkhead to the Eclipse hood opening,
a 90 degree elbow into the opening and another 90 degree elbow
to go down into the tank. The overflow drains at the bottom
of the main tank where clean, fresh water and good circulation
are most beneficial.
I later purchased a vertical UV unit and incorporated this
into the overflow. Water now flows into the UV sterilizer,
through it, and then out into the main tank. Because of the
design of the unit, I discarded the PVC in favour of clear
I wanted the top of the refugium open for air/gas exchange
so I didn't want a hood. I knew that the macroalgaes I hoped
to grow in the tank would prefer light in the red spectrum
of the average horticulture grow light (most corals and coralline
algae thrive under a more specialized blue light spectrum). Finally, because of my desire to make it "fry friendly,"
I also didn't want the lights at the top of the tank.
Lighting turned out to be my least challenge. I purchased
a couple of inexpensive clamp-on fixtures and installed 60-watt
grow bulbs in them. I attached the fixtures to the shelf beneath
the refugium so that light would be provided from the bottom,
not the top, of the tank.
I also took wide black electrical tape and wrapped it around
the top of the tank to darken it, and to hide the spray-bar. I will probably eventually devise a way to cover the top of
the tank to darken the surface and thus discourage the fry
from swimming toward it.
Because I already had a deep (denitrifying) live sand bed
in my main tank, I didn't need much depth in the refugium
and, with only about 10" to work with below the spray
bar, there wasn't much room.
I had purchased several 40-pound bags of Home Depot Playsand
for about $5 a bag. This sand is a fine grade aragonite and
just about exactly the same stuff that aquatic stores package
differently and sell for $50 a bag. If you can find this stuff,
it's great for aquariums. Just make sure you buy the Caribsea
variety and not the regular Home Depot sand, which contains
silicates. I was fortunate to purchase my sand from a local
reefer who imported a pallet for his tank. I believe that
the Caribsea sand is only available at Home Depots on the
I used about half a bag of the sand to create a depth of
Critters and Macroalgaes:
The sand bed in my main tank was full of very diverse life. Over a year earlier, I had purchased a Sand Activator kit
from Indo-Pacific Sea Farms, and had subsequently ordered
GARF grunge and gotten additional sand from several local
LFSs and area reefers. I moved about a cup of that sand to
Aquatics, I purchased the refugium flora and refugium
fauna kits. I was very pleased with the quality and quantity
of the macroalgaes in the flora kits but I was very displeased
with the fauna kit. IA was out of copepod cultures when I
ordered, and it didn't seem like they made any substitutions. It was a lot less stuff than I'd gotten from IPSF.
I also purchased a ball of sea moss, some sea grass and the
green amphipods from Ocean Rider. If you are placing an order
with OR and wish to start a refugium, Carol offers a nice
variety of macroalgaes you can add and will help you choose
species that will work within your available lighting. The
amphipods have proven to be one of the most prolific breeders
in that tank, and they are just adorable.
A word of caution, however. Whatever you buy and wherever
you buy it, check carefully for unwanted critters. Although
I can't with certainty identify the sources, shortly after
adding the macroalgaes, my refugium broke out with a disastrous
case of aiptasia, anemonia, and hydroids. I think I was able
to eradicate most of the hydroids (I only saw 2 or 3) but
I'm still battling aiptasia. The peppermint shrimps I added
recently seem to be doing a good job of taking care of it
IV. Total cost
The following are merely estimates-for items that I already
had, I included a reasonable value if you needed to purchase
them. (I probably don't really want to know this. )
10-gal acrylic tank
UV Sterilizer (15 Watt)
Clamp-on light fixtures
IA (Refugium Flora,
Fauna and shipping)
OR (Sea Moss,
sea grass, amphipods)*
|*OR costs do not include
shipping because I was already placing an order with them.
V. Was It Worth It?
The answer is a resounding YES!
I can't even explain the feeling of satisfaction I got when
I first plugged in the Rio, heard the water rise and then
start streaming out of the spray bar, fill the overflow and
then effortlessly flow back to the main tank. I checked carefully
for leaks and found none. The sense of accomplishment in building
something that worked so beautifully was a reward in and of
I've had mixed results with the macroalgaes. Some thrive
in this refugium (feather, grape caulerpa) while others, particularly
the sea grasses, have just turned brown and withered away. Nothing has grown tremendously, as I had hoped. Nonetheless,
there has been no measurable nitrate since I added the refugium,
and I've noticed an obvious decrease in the amount of problem
algae in the main tank, since undesirable algae now has to
compete with the macro's in the refugium.
The growth of critters has been fascinating. I used to really
enjoy watching the 'pods who, for obvious reasons, disappeared
as soon as I added horses to my tank. The refugium has a plethora
of 'pods and other critters.
The reverse photocycle has completely stabilized pH. I run
the main tank from 8 a.m. to 8 p.m. , and the refugium from
8 p.m. to 8 a.m. My pH is at 8.5, whether I measure in the
morning or evening.
There are two benefits that I hadn't considered. First, the
overflow chamber makes a great feeder. I've put a bunch of
red feeder shrimp and brine in it when I was leaving for a
few days and most of them eventually get caught in the overflow
and end up in the main tank. When I returned from a vacation,
I noticed my horses all hanging around the exit of the overflow,
waiting for more red shrimp. It happens slowly enough that
there is nearly a constant supply of food.
The other benefit is that the refugium makes a nice infirmary. When want to isolate a horse for feeding or recovery, the
refugium is a good place to keep an eye on him, let him feast
on the critters for a few days, or feed him special foods
that I don't want the others to get. Putting him in the refugium,
which shares a water source with the main tank, avoids the
shock of moving into water with a different temperature, pH
or chemical makeup.
As for using the tank as a nursery; again, mixed results. Two of my barbouris were in the refugium and the male unexpectedly
gave birth to a small brood on Dec. 31. Unfortunately, I didn't
notice the babies until late in the day, and most had been
killed by aiptasia. I immediately added three peppermint shrimp
that took care of a good deal of the aiptasia within a week.
Again on January 12, my barbouri had a brood, this time consisting
of over 100 babies that I noticed immediately in the morning. I didn't have time to do anything with them and, as I had
another vacation planned, wasn't sure if I wanted to put the
time into rearing them when I knew I'd be gone for 10 days
at their 4-week point. (I was also concerned that they might
be premature as this was such a short gestation period and
they seemed much smaller than the brood born 12 days earlier. )
I noticed that they were having trouble hitching but the spray
bar did its job-the force of the spray bar is pushing down
the babies trying to reach the surface. Some of the babies
have survived feeding on the copepods and rotifers in the
refugium, without any additional feeding. It's hard to say
how many there are, as they are hiding among the macroalgaes.
VII. What I'd Do Differently
The only thing that has really displeased me about the design
is the placement of the bulkheads. Because they're on the
bottom of the tank and because of the design of the stand,
the refugium tends to tilt to one side or the other, causing
the spray bar on the higher side to be more of a drip bar. If I were to do it again, I'd plumb it from the back instead
of the bottom. That's really the only change I'd make.
VI. Future Additions
Because of the plumbing, I had to remove my protein skimmer
from my main tank, and I haven't yet figured out how to incorporate
one into my present system. Right now, it doesn't seem to
be a vital piece of equipment but I may add one in the future.
I'm not completely pleased with the lighting and may at some
point upgrade it to allow for better growth of sea grasses. I'd also like to add a mangrove.