Gudmundur Geir's (DNA) Reef Aquarium
an honor being featured here on Reefkeeping Magazine
and Reef Central with the tank of the month. My name is Gudmundur
Geir, and I live in the Icelandic capital, Reykjavik.
It all began in 1990 with a space in my
living room that needed to be filled. I bought a used 120-gallon
tank mainly for aesthetic reasons and filled it with tropical
freshwater fish and aquatic plants, but soon the hobby got
hold of me and I was really enjoying it. After a year or two
I built a 300-gallon tank and began keeping African cichlids.
I always wanted to move into the saltwater hobby, but it was
not an option since nobody here in Iceland was importing livestock
in the early 1990’s. I had to wait until 2001 for my
dream of a saltwater tank to come true. By then, two small
pet shops had begun importing saltwater livestock on a small
scale, so I made the transition even though their prices were
astronomical, ranging from 2-20 times the normal U.S. prices.
Most of the knowledge I have on reefkeeping is from Reef
Central and the web. I researched for months before starting
my reef aquarium because I was determined to do it properly.
I read with great interest what experienced reefkeepers were
doing, but still I tend to go my own way.
glass in-wall tank
30”x 35”x 76”
Tunze circulation pumps
sump return pump
watts 10,000K metal halide
watts of T5 fluorescents
In 2003 I bought a
new apartment, and of course the main criteria for its selection
was how well it would accommodate my in-wall tank design.
The new tank was going to be built with simplicity in mind,
and was planned to be a low maintenance tank lasting for at
least 10 years. A lot of thinking went into its design and
layout, and that was time well spent since only 80-100 hours
went into the building, with me doing almost all the work.
The whole project was rather cheap to build, costing around
$4000, including skimmer and calcium reactor. The tank turned
out to be a reefkeeper’s dream and now, 18 months later,
there is little I would do differently if I had to do it again.
The tank, which has a stainless steel frame, was the largest
my new apartment would allow. Every guest that visits really
likes its large dimensions. It is as deep as my hands can
reach, and everything is easily accessible within it, and
the depth allows for some creative aquascaping. The bottom
shell fragment substrate consists of about 200 pounds of finely
crushed seashells pumped from the bottom of a nearby bay.
Because I didn’t want all of this sand to be hidden
under piles of rock, I left a large, quite prominent open
area that’s easily seen when viewing the tank.
I arranged the estimated 200 pounds of live rock to give
a sense of dimension and to do something different from the
conventional “reef wall.” I really like how it
turned out, but I will need to make some changes as the corals
grow and need more space.
The sump is a 100-gallon container with ample room for the
skimmer, calcium reactor, macroalgae growth and marine life
that’s unsuitable for the main tank such as a mantis
shrimp, a rock boring urchin and a few fish I keep for a friend.
Plumbing, Circulation and Top-off:
I gave this subject
a lot of thought. Many reefkeepers go to such great lengths
that they end up with a complex maze of pipes. That did not
appeal to me, so I went the other way. One overflow is more
than enough for this tank, and the standard Durso style standpipe
with its submerged intake was the obvious choice. From there,
the water flows directly through the skimmer and then to the
sump. I installed a second overflow for surface skimming,
as well as for safety, in case something was to clog the Durso.
The return pump doubles, indirectly, as the skimmer’s
pump. The flow is adjusted for the amount required by the
skimmer to produce the best results since it is gravity fed.
The plumbing is simple with only a few feet of pipes, and
it works like a charm.
The two Tunze circulation pumps, along with the tidal controller,
do a great job maintaining a strong current throughout the
tank, even behind the loosely stacked rocks. The automatic
top-off mechanism, which adds freshwater directly from the
tap, is synchronized with evaporation via float switches,
for safety. There is no need for a fancy water purifier since
the water here in Iceland is naturally pure. A large fan blows
across the water’s surface to remove heat from the lights
and to speed up evaporation.
Left: A programmable timer with four relays to
control the lights, fan and automatic feeder.
Middle: The Tunze controller is in the middle
for the Tunze stream pumps.
Right: A Tunze water level alarm with three float
switches connected to
open or close the automatic top-off solinoid.
It's my firm belief
that the fewer fish I keep, the more successful I’ll
be with the reef, and the less the tank will get polluted.
So, the only filtration is a Deltec skimmer and I make sure
not to overfeed. I also grow macroalgae in the sump for a
bit more nutrient export. I run a Deltec calcium reactor to
maintain adequate calcium levels for good coral growth. Water
changes are done sparingly. For an ”experiment,“
I went the entire first year without any water changes at
all, and all went well as I had expected. The corals looked
fine and seemed to grow well, but I noticed subtle changes
for the better after the first water change, and I now do
occasional periodic water changes. I use carbon most of the
Three 250 watt 10,000K
metal halide lamps provide most of the lighting. I positioned
them as closely as possible to the tank’s front rim,
at an angle pointing slightly toward the back of the reef
to have a little more light shining at the fish and corals,
and less shadows, for optimal viewing through the front glass.
Two pairs of 80-watt T5 actinic fluorescent bulbs add a slight
blue hue to complement the metal halides’ color. The
photoperiod is nine hours from noon for the metal halide bulbs,
and 16 hours from 7:00 AM for the T5’s. Coral growth
is quite good, but it would probably be a little faster with
a longer photoperiod on the metal halides. The sump is lit
with four normal output fluorescent bulbs from 6:00 AM to
I have the utmost
respect for all life, so when any animal in my care dies I
ask myself if I’m doing the right thing by keeping it
far from its natural environment in conditions that I can’t
match, but can only simulate to some degree. Then again, life
in the ocean is all about life, death and survival, and I
feel I am doing my best to provide conditions that are as
natural as possible.
I get the most satisfaction from starting off with tiny coral
fragments and nurturing them into glorious larger coral colonies.
I plan to be in this hobby for many years, and aquaculturing
is my preferred way of stocking the tank. It does not seem
to be good business for the pet shops to sell small fragments,
and these are available only from fellow reefkeepers. Fellow
hobbyists with established tanks are so few in Iceland that
fragments are very difficult to find. To me, keeping marine
life is all about stability, and is a balancing act. I think
I’m doing a fine job with a minimum amount of interference
and lots of patience, to keep my tank alive and well.
A close “friend” of the Achilles tang who shares
its interest in following people around who are close to the
tank. He is skilled at picking up shells and flushing amphipods
and other small crustaceans out of them.
This fish gets most of the attention, as its main goal seems
to be to stay as close to me as possible when I’m viewing
the tank or walking by it. It’s also a strikingly beautiful
fish and looks like it’s always in a good mood. This
fish never sleeps and is seen swimming back and forth even
in total darkness. I was going to light the sump during the
night, but changed it to daytime lighting to let this guy
get some rest during the night.
I brought this fish for Aiptasia control and it did
a perfect job of ridding the tank of the pest anemones. It’s
also quite a feast for the eyes.
This fish looks like Homer Simpson and is almost as much fun.
It makes up for its lack of color with its unique characteristics.
During feeding when the Tunze pumps are off, this fish swims
right into them. I don’t know if it likes to “play
cool” or if it’s a stunt to impress the tank’s
other inhabitants and me.
Neon Goby pair:
Inseparable, these fish stay close to one another and provide
a valuable cleaning service, especially for the tangs.
Maroon Clownfish pair:
This pair spawns every few days. Their home is the large long-tentacle
False Percula Clownfish pair:
This pair stays in the M. doreensis anemone, placed
near the middle of the tank, and are subordinate to the Maroon
Although I’ve had this fish for two months, I’ve
seen it only a few times since it stays behind the rocks.
A very shy and inactive fish, the very opposite of the active
Corals and Anemones:
Briareum (formerly Pachyclavularia violacea)
I’m far from where I intend to be with the corals.
Foliose Montipora are my favorite, and a few large
ones will dominate the tank in a few years, but zoanthids
and soft corals do not fall far behind in their beauty. SPS
and LPS are equally interesting as far as I’m concerned,
and I’ll keep both to the very end. I do not want lots
of small, different kinds of colonies I’m just waiting
for the corals to grow and fill up the empty spaces.
The anemones are my pride and joy, even though the long-tentacle
one takes up almost a quarter of the tank. It deserves its
own space and the Maroon clowns enjoy the protection it affords
and will vigorously defend it. The green carpet anemones with
their powerful stinging cells seem to be a death trap for
other inhabitants. Nothing will escape them if caught. Still,
I know for sure of only a starfish and two urchins that have
fallen prey to them, but a few fishes are likely to have gone
the same way. How they are able to eat urchins with long spines
and suck their insides out of their test shows their ability
These are the most interesting marine animals, and I intend
to have as many as I can within the space and ethical constraints
of the tank. At the moment, there are two brittle stars, two
cleaner shrimps, a rock boring urchin, a mantis shrimp living
in the sump and around 100 hermit crabs and snails, to name
a few. Unusual and fascinating invertebrates such as the Scutus
slug and Ampheneura chiton that have regrettably died
are the type of animals I’m looking for, although I
hope to find species that have a better survival rate in captivity.
Just like humans need
a variety of foods, the same applies to marine life. The fish
are fed a range of flake foods and various pellets. They also
get frozen Artemia and Mysis shrimp, and occasionally
live Artemia. When I feed the anemones biweekly, shrimps
and brittlestars get the remains of the food, consisting of
octopus, shrimp, squid, mussel or other seafood. The tangs
seem to have an endless appetite, so I feed often, but sparingly,
each time. I have an automatic feeder on standby to be used
when nobody is home for days at a time.
The Maroon clowns
spawn every few days and it’s unfortunate that none
of the fry survive. It’s not for lack of attention from
the clowns; their dedication for taking good care of the eggs
is admirable. Unfortunately, I have not had the opportunity
to properly rear the fry to juveniles.
The repeated spawning of the Green Chromis was a joy to watch,
with violent, fast chases in between slow, gentle moments
while spawning on the rocks. This kind of action is what makes
reefkeeping so interesting.
I had a beautiful Montipora capricorni, that had grown
quite large in just over a year, but it started deteriorating
from the center and spread toward the edges at alarming rate.
I hoped it would subside and the coral could be saved, but
that was not the case and only a few fragments broken from
the edges survived. Now I’ll have to wait at least another
year for it to recover.
The Hydnophora and the Acropora had a gap between
them which I thought was wide enough to prevent competition,
and they had been that way for months when suddenly the Hydnophora
struck with the full force of its mesenterial filaments, killing
at least a third of the Acropora.
I have two rock boring urchins, and I was quite happy with
these free hitchhikers until they grew larger and started
to knock rocks and corals over. Big corals and rocks up to
two pounds get upended and the urchins have done some considerable
damage, both directly and by knocking corals on top of each
other. I've managed to banish only one of them to the sump,
but the other stays hidden and can be removed only if it were
dead, or attached to a rock.
One night right after the main lights went out a spawning
event occurred (see pictures below), releasing huge amounts
of eggs and sperm into the water column. I suspect it was
some of the corals that spawned, but it was quite a show with
only a few inches of visibility. The skimmer was extremely
active, and I emptied many cups of odd looking organic matter.
Even though the water didn’t smell foul, the two Green
Chromis I’ve had for years perished along with two cleaner
shrimps. The next night at the same time, another smaller
wave of spawning occurred, but fortunately without any loss
of livestock. Six weeks later, spawning occurred again for
two nights in a row on a smaller scale, so perhaps this will
be a regular event in my reef aquarium. I have yet to see
any new life come out of the spawning events. I also learned
a lesson while tending to fish belonging to a friend whose
tank had leaked. Because of stress, the fish were soon infested
with parasites that also moved onto my fish, killing one of
mine and six of his.
Recently, I gained
a great deal from a diving trip to the Red Sea in 2003. It
broadened my understanding of marine life and I urge everyone
who is able to visit and experience a coral reef in person
to do so as it greatly enhances the experience and interest
in the hobby of reef aquaria.
You can follow my tank's development as it
ages on my website.
Feel free to comment or
ask questions about my tank in the Tank of the Month thread
on Reef Central.