March 1996

I have already received a few letters concerning failed attempts at
reef aquaria. I am somewhat dismayed at the information being
provided to hobbyists as to what equipment they are required to have
in order to be successful. A common thread is that many of you are
trying to setup systems on very limited budgets and you are not
spending your money wisely, while others spend their hard earned cash
on needless pieces of equipment or elaborate automated systems. Often
the problem is complicated by using small tanks, under 75 gallons.
Not to say that small reef tanks won't work, they will, but you
really need to understand how a reef tank operates to do so
successfully over the long term. One very common problem I see is
that many of you have success with some organisms but not all. My
question then is, why continue to spend your money on difficult to
keep organisms and the technology required to keep them? Why not just
stay with what does well in your system? The freshwater plant people
learned this lesson a long time ago!

So what should you do if you want to setup a reef tank on a limited
budget? First of all you need to understand that there are three
important parameters that you should concentrate on: lighting,
filtration and water chemistry.

Many of the organisms you will want to keep in a reef tank require
light and lots of it. You cannot skimp on this parameter. The problem
is that the amount of light you will need is totally dependent on the
types of organisms you want to keep. If your lighting is too weak
some will do well but most will not. If the lighting is very strong
the same applies, some corals and clams will do very well, others
will react badly to the intensity. You will then need to have areas
in the tank where you can place organisms that require less light.
Now I know that this sounds rather vague but until you know what you
want to keep you cannot get specific about what type and amount of
lighting you will need. The intensity required also depends on the
depth of the tank used.

Within reason, it is safe to say that if you are using fluorescent
lights only, the more you can put over the tank, the better. Or you
can use the newer very high output (VHO) lamps and use fewer of them.
Metal halide lighting is generally reserved for tanks greater than 20
inches in depth, but can be used on smaller tanks, again depending on
the organisms one wishes to keep. Signs of inadequate lighting can
include excessive vertical extension in animals such as mushroom
anemones, lack of growth or stunted growth, poor colour, and
darkening of the tissue followed by gradual lightening as the
zooxanthellae die- off. Signs of too much light include lack of
extension of polyps and body tissue, and excessive lightening (often
rapid) of the coral.

It is very difficult to do lighting well on a limited budget unless
you have access to used, industrial or bargain priced equipment. But
this is one area that you cannot afford to skimp on; your whole
system depends on it.

Filtration is a rather simple consideration for reef aquaria. You
need at least some form. Most aquarists today are still using live
rock and by itself, live rock, when healthy, will easily handle the
biological filtering needs of the tank. When combined with a live
sand substratum, you have all the biological filtration bases
covered. You do NOT need to have a trickle filter for biological
filtration, save your money. The same goes for canister filters,
undergravel filters, and all the various hang-on-the-back doohickeys
out there. The only piece of equipment you will need is a good
quality, and well designed protein skimmer (foam fractionator). There
are many good models out there designed for various size aquaria or
if you are at all handy, you can build your own. There are skimmer
designs available on the Internet, Compuserve and America Online, not
to mention in various books. The best designs use a dedicated water
pump to feed the skimmer, allow for a large flow rate of water
through the skimmer, inject a great deal of air, can be easily and
thoroughly dismantled for cleaning, and have a wide neck leading to
the foam collection cup. The last point allows you to pump a great
deal of water and inject a lot of air without having to worry that
small adjustments in the water and/or air flow will quickly overflow
your skimmer. Either continuous or periodic usage of small amounts of
activated carbon will assist in the removal of organics and prevent
yellowing of the water. I am sure there are those of you out there
who question what I have stated. But based on my own experiences and
those of thousands of other successful reef aquarists across several
continents, the above is all you need in the way of filtration.

Water chemistry is a bit of a bugaboo for many aquarists. Few
understand it well, fewer still seem to want to be bothered with it
for whatever reason. The simple fact is that you will need to monitor
and understand the water chemistry of the tank if you want to be
successful and if you want to be able to trouble-shoot potential
problems. There are three parameters that are essential to know when
dealing with aquaria that contain calcifying organisms like coral:
calcium, pH and carbonate alkalinity. Calcifying organisms require
both calcium and carbonates in order to form calcium carbonate, the
framework of their bodies. Calcium levels should be between 380 and
480 mg/L to ensure good growth. Carbonate alkalinity can be measured
in either milliequivalents per liter (meq/L) or as German degrees of
hardness (dKH). Some kits such as those manufactured and sold by
LaMotte and Hach measure in ppm of calcium carbonate. It does not
really matter which units you use since they can all be converted
from one to the other. I'll stick with meq/L and dKH since these are
what most hobbyist kits measure. To convert meq/L to dKH multiple by
2.8, to convert dKH to meq/L divide by 2.8. Alkalinity levels should
be between 8 and 14 dKH in order to ensure good growth rates. The pH
level should be maintained between 8.0 and 8.4. Although there are
test kits available to measure pH, as I mentioned in last month's
column, it is much more economical in the long run to purchase a pH
meter. These can be bought for under $100. If you can maintain these
three sets of values then you are a long way towards being successful.

Undesirable algae

As I mentioned last month, one of the most common problems reef
aquarists experience is the presence of undesirable algae such as
slime and hair algae. Both of these are rooted in the same common
problem: excess nutrients in an unbalanced aquarium. When aquaria are
first setup it is perfectly natural to experience a bloom of these
algae, which eventually subsides. The problem comes when they do not
disappear or continue to reappear. At this point the aquarist must
examine all sources of nutrient input. The two main culprits are
nitrate and phosphate. In today's reef aquaria nitrate levels are
usually not of concern unless there is a significant input of nitrate
either through excessive feeding, the use of efficient nitrification
filters or nitrate-laden top-off water used for evaporation.
Phosphate can enter the tank through food and through top-off water.
Algae can also liberate stored reserves in rock and sand. In fact,
live sand beds can store a great deal of phosphate. One paradox is
that aquarists often report very low phosphate levels yet have
undesirable algae problems. The problem is that hobbyist test kits
only measure inorganic forms of phosphate. This is readily used by
algae and corals, and removed by skimming. However, organic forms of
phosphate can then become new sources of inorganic phosphate. This
explains why hobbyists often report low levels of phosphate; the
inorganic phosphate the kits are designed to measure is rapidly
depleted but the organic pool is still available to replenish the
supply.

The key to dealing with undesirable algae is to limit the import of
nutrients and increase their export. Imports can be reduced by using
pure fresh water for make-up and water changes, using only high
quality foods and avoiding overfeeding. Exports can be maximized by
using an efficient protein skimmer, activated carbon, and the use of
grazers such as tangs, crabs, and fish.

Next month, more questions!