By Tommy Dornhoffer
The aquarium hobby has grown by leaps
and bounds since its inception. These leaps have largely been made possible by
our growing understanding of the needs of our livestock, vertebrate and
otherwise. As our knowledge about these animals’ requirements grows, we are able
to provide more natural and pleasing conditions for our creatures. However, the
dramatic increase in technology and equipment has led to what some consider an
alarming overuse of mechanics. I have been an aquarist for only six years, but
in that time I have also perceived this alarming trend towards using technology
as a panacea to cure our aquariums’ ills. Perhaps the time has come to stop and
ask ourselves: Is this wonderful technology really beneficial to our
animals?
Let us first consider two aquariums.
These reefs are representative of the two opposite ends of the equipment
spectrum. One employs immensely powerful lights, enough filtration to deal with
a city’s wastewater for a year, and more automation than a small computer firm.
On the other hand, the second reef employs only simple lighting, minimal
filtration, and some simple devices to make things a little easier to keep up
with. Yet, looking at these two tanks, an amateur would not be able to tell a
difference; they are both stunning recreations of the coral reef, and both
aquarists are to be commended for their skill.
This anecdote illustrates one very
important item: the common link among successful and beautiful reefs is not
incredible equipment and budgets, but a simple and thorough understanding of
biology (and chemistry) and its applications to the home aquarium. In other
words, the key to success is not necessarily having the biggest and best
equipment but knowing how to use it. That leads me to the central point of this
article: Are the wonderful advances in technology truly benefiting the hobby, or
are they merely false pathways to success? I will especially delve deeply into
three areas: lighting, water motion, and filtration. Of course, any article
would be incomplete without mentioning other areas, so I will touch on those as
well as mentioning the problems of the currently widespread fad mentality.
A sun in
a Bottle: A Critical Look at Developments in Reef Aquarium Lighting
|
Metal halide lighting is intense -
sometimes too intense. It also covers a limited area with light.
Metal halides shouldn't be considered the answer to all lighting needs,
although it works well for deep displays like this one at the PPG
Aquarium in the Pittsburgh Zoo. Photo by Adam Cesnales |
The field of aquarium lighting is
incredibly diverse, and it becomes more so with each passing year. It is only
natural then, that aquarists make sweeping generalizations in the interest of
simplicity. However, few have stopped to ask themselves if these generalizations
remain legitimate. For instance, a mindset has developed that metal halide
lighting is the pinnacle of aquarium lighting, and is the best setup for
any reef. Of course, any intermediate or advanced aquarist knows the flaws
inherent in that generalization. While metal halides may be well suited for
shallow-water inhabitants or for very deep tanks, there are certainly many
applications for which they are not well-suited. That said, metal halides – and
most other lighting systems – will work in most situations; it’s simply a
matter of
optimizing the conditions.
As I said, many aquarists are aware
of the flaws in blanket metal halide use (or blanket anything use); but
many novice aquarists take the blanket-metal-halide recommendation all too
seriously, leading to – in the worst-case scenario – a lighting system that is
completely inappropriate for the situation. These situations are actually few
and far between, but it is worth noting that mushroom corals – a group which is,
of course, a primary beginner coral – have a relatively low ability to adapt to
high-light conditions. In most cases, though, the end result is wasted money,
and I know of some would-be hobbyists who were turned away because they
incorrectly perceived pricey halide systems as an inevitability. With this
article, I hope to emphasize that there are other, cheaper ways of achieving our
goal (providing conditions for our tank inhabitants to thrive).
This leads me to one of the main
points of this little article: Rather than “brute-forcing” aquarium light by
applying a general recommendation of extraordinarily powerful lights for all
situations, aquarists should seek to use light intelligently, developing a tank
plan which includes all aspects of the reef’s future. This should start with the
intended inhabitants and build everything else around that piece of information.
For instance, if one intends to set-up a reef featuring Mushroom Anemones, he
should realize that these animals can do quite well with light and water motion
which some would consider to be insufficient. Moreover, anecdotal evidence
(oxymoron though that may be) suggests that Mushrooms actually prefer
dimmer conditions. Metal halides could work with this theoretical setup, if the
aquarist takes some measures to prevent over-illumination, but the aquarist can
save money and possibly headache by using a cheaper and simpler lighting system
like power compact or VHO fluorescents. Of course, an exceptionally deep tank
might require more intense lighting, and that is something to take into
consideration. This also brings up one inherent problem with keeping “mixed”
reef tanks: it can be difficult to provide conditions that satisfy all the
tank’s inhabitants, which often leads to compromises. However, many clever
aquarists have found ways to circumvent this problem, but that is really beyond
the scope of this article. The point I wish to make is that an aquarist should
tailor light to a particular setup, rather than following a sweeping
generalization or stocking a tank based on the equipment. I also wish to point
out that this is in no way a new or revolutionary idea. Hobby “giants” have been
proclaiming this for some time. It is important enough, however, to be repeated
at every possible opportunity.
Effects
of Too Much Light
Over-illumination has many potential
negative effects, including coral bleaching and UV burning. However, many
aquarists do not encounter these obstacles, both because of good acclimation
practices and the inherent ability of corals to adapt. Instead, there are other
actual effects of “light overkill.” Chief among these is increased
temperature due to the light, which can in turn lead to bleaching and other
mortality. Another potential threat is the increase in algal growth. It is
notable, though, that all of these side-effects can be alleviated with a little
know-how: temperature problems are corrected by raising the lamps and adding
fans (or even a chiller) and many articles and books (all of which are more
authoritative than myself) have been written concerning algae control. Why then,
did I even mention these aspects of light when they are so easily corrected? The
simple answer is that I wish to be complete. Truth is, the biological effects of
over-illumination, because they are so easy to correct, are only a small part of
the problem (but they are effects which still exist!). The main item which I
have a hard time accepting is waste.
I have read many discussion threads
questioning whether 250 watts of HQI over a 10 gallon nano-reef is too much. My
answer is always the same two-parter: 1) No, it’s not too much, if you raise the
light high enough above the tank and watch temperature, but 2) why spend the
money when a much cheaper and simpler setup will get the job done just as
effectively? Aquarists seem to be of the mindset that more light will always
increase health, growth rate, and color. This is true only to a point, and
given certain conditions. First, corals need some source of nutrition other than
light. Most of the time, this nutrition is provided simply by feeding the fish.
However, in tanks with extreme nutrient export relative to import, the corals
will actually starve and slowly die (more on that later). It also notable that
coral growth rate will “plateau” at a certain point: no matter how much light is
added after this point, the coral simply cannot grow faster. The color argument
is similar: at a certain point, corals will keep their color; a coral that is
naturally brown will not turn green under even the most intense light (though it
will at one point turn white). So, lighting overkill won’t necessarily harm
the aquarium, but it often represents resources –financial and mental – that
could be better applied elsewhere. Novices just starting their wonderful journey
should especially take heart from this: you do not need incredibly
expensive and complex equipment to experience success.
So, to conclude this section, having
extremely powerful lighting is not nearly important as having the correct
lighting. Sweeping generalizations recommending incredibly intense light for all
applications should be avoided, because not every application requires such
lighting, and some applications might even suffer from it. At the very least,
the use of very powerful light over every reef represents an unnecessary use of
resources. Aquarists with a limitless budget, perhaps, can buy 1000 watt metal
halides for everything they create (as long as they take sure to use the light
correctly). The rest of us can take heart knowing that that such light is
needed in only a small portion of all reef applications.
Much Ado
About Something: Water Motion
Another area that has seen
significant growth is the understanding, use and application, of water movement
in the reef. In stark contrast to my views on lighting though, I think water
motion is something that is still often ignored. Many novice aquarists overly
concern themselves with appropriate light while ignoring light’s counterpart,
water movement. It is impossible to blame them: it seems every other question on
an aquarium bulletin board is about light, while questions about water motion
are sadly under-represented. However, proper water motion can be more
important than lighting in many ways. Of course, the hobby’s understanding and
use of water motion could use some examination, otherwise it would not have
found its way into this article!
The primary problems with water
movement (in my opinion) stem from a lack of understanding of what exactly
constitutes “good” water motion. Many aquarists still concern themselves with
the turnover rate (that is, how often the tank’s volume runs through a pump).
Turnover rate is indeed something to consider with a filter, but it can be very
deceptive with simple water movement (i.e. a case where water is simply moving,
not going through a filter media). Small tanks especially disrupt the notion of
appropriate water movement; they are so small that an “appropriate” turnover
rate actually represents less movement than is required. Thankfully, many
hobbyists are starting to define water movement in terms of feet per second
or similar measures. However, this is something that needs some work, as is
providing correct water motion.
Many aquarists try to get incredible
water motion using only a few powerful powerheads or strong return pumps from a
sump. However, many accomplish this by using only one or two very powerful pumps
when many smaller ones actually provide a better “flow field.” What makes a
proper flow field is a subject that has received much attention from the
experts, so I do not want to go into much detail here. However, it bears
repeating that a lot of smaller flow sources are usually (but not always!)
preferable to one or two large ones. Of course it is also important to keep in
mind what the inhabitants of the tank want. Some filter-feeding corals actually
need strong laminar (one-direction) flow. Equipment such as wavemakers
and waveboxes are also very beneficial, but budget reefers can again take heart:
proper water movement can be provided with inexpensive powerheads. It
should be noted though, that all pumps have the potential to increase water
temperature. This is something to always keep in mind when planning a tank.
[Editors note: The limitations of using one or two large
pumps can be largely overcome by the use of multiple returns or "manifolds".
Plans for these abound on the internet.]
As with lighting, one of the more
common problems is providing inappropriate conditions for the tank’s specific
inhabitants. Not all corals come from areas of high flow and there are many
popular species that do not appreciate extreme currents. An aquarist should
always keep in mind what he is planning a stocklist (is anyone else finding that
phrase somewhat grating at this point?). It is notable that those corals
which require intense light also tend to require heavy water motion (hence these
areas of the reef being called “high energy”).
Water motion is in stark contrast to
lighting in that it has not yet, in my opinion, reached its peak of development.
More aquarists might want to consider shifting their attention from light and
redirect it to water motion. However, sweeping generalizations should once again
be avoided: not all reefs call for extreme water motion, though that problem is
much less pronounced than the similar one with lighting. The one true problem is
the use of one or two very powerful pumps to provide the appropriate turnover;
the use of such pumps exclusively might actually cause more problems.
Too
Pure? A Look at Common Filtration Practices
Both as an online hobbyist and
through my work at the local fish store, I have heard many stories of corals
suddenly losing color or even dying after a new piece of equipment was
installed. The actual biological processes involved can vary widely, but the
bottom line is that this new equipment did one of two things: It either made the
water too pure, or it cleared the water too quickly. Although these two items
sound similar (and are similar) there are some important distinctions. I will
mention these a little later. First, I want to say to all the readers what I say
to anyone considering a new filter system,“Don’t fix what ain’t broke.”
|
Maybe if Tim "The Tool Man" Taylor
became a reefkeeper, he would choose this enormous skimmer on display at
the H&S booth at the Interzoo trade show. Although this skimmer is
designed for commercial use, it certainly is an example of the potential
that exists for skimming excess. And for the keen eyed reader...
yes, that is Anthony Calfo in the background and yes, he is giving you
the evil eye for even dreaming of putting this skimmer on your 90 gallon
reef! Photo by Adam Cesnales |
All too often I have heard or read
stories of perfectly healthy reef aquariums collapsing or otherwise being harmed
after a radical improvement to a filter system. Many, if not most of these reefs
were doing perfectly well and many were quite beautiful. However, the
reefkeepers simply could not resist the urge to buy the best and newest filter
system. They just knew that their livestock would be even healthier
afterwards. In actuality, the massive disruption of the system combined with
radically new tank conditions led to problems. That said, there are indeed many
tanks that could benefit from the addition or revision of filtration. The key,
though, is to move slowly. Just as one would acclimate his livestock for the
first time, one must make changes – including improvements – slowly enough to
allow livestock to adapt. Almost all of these cases I have dealt with have been
ones of mortality caused simply by the conditions changing too quickly. In my
experience, one of the most notorious additions is the sudden incorporation of
lots and lots of activated carbon.
Activated carbon does two things
which have the potential to shock corals. First, it removes trace elements. This
should not be a reason to exclude the use carbon. However, the sudden addition
of carbon without the supplementation of trace elements (by the way, we
should always test the levels of any element which we add to prevent an
overdose) can shock livestock. Moreover, carbon can remove some compounds (good
and bad) so quickly that the corals, which have grown used to the concentrations
of those compounds are shocked by the change in water chemistry. The second
thing carbon does is remove coloring agents, making the water clearer. This is a
very good thing! However if the water becomes dramatically clearer, the corals
will need a chance to adapt to the new light field. Denied this chance as would
be the case with the sudden addition of carbon, they can actually bleach. So,
what can aquarists do to add carbon safely? Following the advice of many
experts, carbon should be added and changed frequently, but in small amounts.
It’s a simple solution, but it’s a solution to a problem which is often ignored
until it’s too late.
So, suddenly adding filtration can be
a problem if it happens too quickly. However, there is another threat to
overzealous filtration, one which has only recently made itself apparent. With
all the advancements in reef filtering technology and methods, the hobby has
actually advanced to the point where people can and do make their water too
clean. That statement may sound outlandish to many aquarists but it’s
actually a situation popping up more and more. Basically the problem stems from
the belief that the reef environment is truly nutrient-poor. However, to
paraphrase Anthony Calfo, the reef is not so much devoid in nutrients as it is
using them too fast to be detected (what Mr. Calfo and others call
“nutrient-concentrated”). There is a massive amount of nutrient exchange
occurring on the reef; the nutrients are simply used by reef life (including
algae) faster than it is used. This dynamic often occurs in the reef aquarium,
but it can be disrupted by the efforts of the aquarist. The combination of
nutrient deprivation techniques such as massive over-skimming, large water
changes, and bare-bottom methods is all too effective, leading to a tank devoid
of all nutrients. This is good for a while, but then the corals start to degrade
and slowly die. This happens because no coral can subsist solely on the products
of photosynthesis; they must have outside nutrients. In most cases, these
nutrients are provided nicely by fish waste, but environments geared toward
nutrient reduction are actually ending up with cases of coral starvation.
Surprisingly, this war on nutrients is often waged in the name of enhanced color
and growth, but it is waged without a good understanding of the complex
interplay between nutrients, growth, and color. This is a subject that utterly
fascinates me, but it can be fairly intense science, and is beyond the goals of
this article. Simply put, no direct correlation has been shown between lack of
nutrients and increased color and growth. Certainly, within parameters,
improving water quality will improve coral health, but many nutrient-deprived
systems are beyond those parameters. [Editor's note:
Another way to understand this problem is to realize that most corals prefer
particulate foods like plankton and detritus particles over dissolved organics.
While super skimmers and aggressive filtration techniques will never reduce
dissolved organics below those on the reef, they will easily strip the water
clean of particulate food items.]
To conclude this section, excessive
filtration can have two negative effects. First, if it is implemented too
quickly, enhanced filtration can shock corals by abruptly altering tank
conditions. Second, extreme filtration can actually lead to true
nutrient-deprived environments in which corals simply cannot thrive. Thankfully,
only a handful or reefs have encountered the latter problem, but novice
aquarists especially should act cautiously when designing a dream filtration
system. Unfortunately, many intermediate hobbyists also fall into the trap of
“super-filtration,” so they also might do well to keep this in mind. In short,
moderation is key.
Are
Algae Evil?
Simply put, no. In fact, algae as a
group are very good. However, it seems that most aquarists consider algae their
arch-nemesis and they go to great lengths to eliminate it. This can lead to some
of the situations I described above. Contrary to many views though, algae are an
integral part of any reef ecosystem. And by the way, I’m not just referring to
the zooxanthellae (symbiotic algae within the coral), free-living algae play a
huge part on the reef as well. Why then, you might ask, does it not take over? I
would reply: how could it take over, with thousands of herbivores grazing a
particular spot in the course of one day? The overwhelming presence of tangs and
other herbivores keeps the algae in check. It grows very fast on the reef, but
it’s eaten faster. Of course, replicating the massive schools of tangs in the
home aquarium can be, well, difficult (if not absolutely inadvisable). However,
the dynamic can be replicated by including a relatively large number of
herbivores, as long as they are not allowed to starve.
I am of the firm opinion that we
should actually cultivate desirable forms of algae in the aquarium. Many books (Reef
Invertebrates, for one) espouse the benefits of algae: they absorb
potentially harmful nutrients and help to regulate different levels within the
system, including pH, oxygen/CO2 , and many others. Of course,
incredible amounts of algae growth might require some work to keep them from
taking over, but I believe the benefits make the work worth it (especially if
herbivores are doing the work for you!).
In summation, the presence of algae
should never be considered a sign that something is wrong. Algae will grow in a
healthy tank. Period. Our job is simply to make sure conditions (especially the
presence of herbivores) favor coral growth over algae growth.
“Aquarists A, B, and C Said I Should Do This. Their Tanks Look Great, So I
should Do This…”
I have heard that statement just a
few too many times. It’s not necessarily wrong, but one should always know the
science behind a particular method before using it. I have been involved in the
hobby intensively for six years, and it seems that as the hobby has grown it has
developed a nasty “fad” tendency, with each year bringing in a new method
everyone has to use or a new coral everyone has to have. The trouble is that
many of these “new” things are not at all new, and many people are changing the
way they keep aquariums without really knowing the pros and cons of doing
so. The latest “craze” seems to be the shift back to bare-bottom reefs. I
hesitate to call this a craze, because I do not wish to demean a method which
has proven reliable. Instead, I wish to highlight that many self-proclaimed bare
bottom devotees have a very poor understanding of the science behind the
methods. This leads to people making dramatic changes for the wrong reasons –
sometimes even altering successful systems! – and that can lead to
disappointment when the method offers no new success to the aquarist.
[Editor's note: Amen!]
Bare bottom tanks are just one new
“fad,” and the praise-worthy work of intelligent aquarists has gone a great
distance towards educating aquarists on the pros and cons of the different
methods (substrate-related and not). Rather than choose a particular method
because it seems “everyone is doing it,” aquarists (novice and advanced alike)
should consider their goals for their tank and how each method will help them
achieve those goals. Most importantly, aquarists should always consider the
reasoning behind a particular “fad.” Does it make good scientific sense, or is
everyone simply emulating the tank-of the-month from a while back. Of course,
emulating a “winning” tank is usually a good way to find success. Just be sure
that the methodology is compatible with the aquarium and the aquarist.
[Editor's note: Can I get another Amen!]
I want to close by mentioning one way
to sift through all the different ideas out there. With huge aquarium sites like
Reef Central, finding good information is not hard; sifting the good information
from the bad information on the other hand, is hard. First and foremost,
keep in mind that there are as many ways about reefing as there are reefers;
anyone who says the method they promote is the only method should be
promptly ignored. Even aquarists who claim something is the best for
any situation should be treated with some suspicion (though not immediately
ignored). In my experience, the best help comes from those who provide not only
a suggestion, but also the reasoning and caveats behind the suggestion. My
favorite answer, though, is the brutally honest “I don’t know.” That statement,
to me, is the ultimate proof of candor and reliability. Finally, get multiple
answers for your questions, perhaps even from multiple disparate sites. One
aquarist can easily be wrong, but it’s a little more difficult for twenty to
miss the mark.
Conclusion
The aquarium hobby has been advancing
by leaps and bounds since its inception. However, every advancement must be
taken with a pinch of salt (whichever brand you prefer, synthetic or natural).
The most important question to keep in mind is this: what benefit does it offer
my individual system? It might also be heartening to know that a successful reef
does not require incredibly complex filtration, small-tsunami-scale water
motion, and sun-rivaling light. Instead, the most important aspect of success is
good husbandry, perhaps coupled with a good and sound understanding of the
science behind the reef. To close, I would like to bring in one of my favorite
sayings about how we should design our reefs: always look to nature; remember
that nature has been doing this for a lot longer than we have, and with a lot
more success. At the same time, also keep in mind that nature wasn’t doing this
with a little glass box and a budget.
Happy Reefing.