By Alexander Girz
Translated by Gary Madl
(This article was originally
written in German by Alexander Girz and translated into English by Gary Madl.
The translation was done to best represent the original text. Unit conversions
are approximate and were applied for easier reading and may not represent the
In this article, I would like to share my
experience in keeping SPS (Small Polyped Stony) corals. The
tank described was established in September 2001 and has been successfully
operated with the ZEOvit system (by
www.korallen-zucht.de) since November 2001. Both the tank and the
equipment have primarily been designed to keep SPS corals.
Let me start with some relevant data about the
Dimensions and volume: 220 cm long x 80 cm deep x 60cm high (approx. 86.5” x 31.5” x 23.5”),
1056 liters (approx. 279 gallons), plus 250 liter sump (approx. 66 gal).
The reef structure is built exclusively with approximately 100 kg
(approx. 220 lbs.) of freshly imported Indonesian live rock.
PowerRiga strip light with three E40 socket metal halide bulbs (BLV 10,000
Kelvin, 250 Watt) as well as four blue fluorescent bulbs (ATI Blue plus 80
Watt). The metal halide bulbs are replaced every 6-7 months. Lighting schedule:
metal halide 7 hours – fluorescents 12 hours.
sump is located in a separate room. It is fed by a surface overflow from the
main tank. The water turn over between the tank and the sump is approximately
2500 liters per hour (660 gph). An externally powered skimmer (H & S
A200-2x1060) with a flow rate of 2000 liters per hour (528 gph) is connected to
the sump. ZEOvit filter material in a ZEOvit filter is set with a flow of
approximately 2000 l/hr (528 gph).
3 Tunze Turbelle Electronic pumps with 4000 liters (1056 gal) each and 1
Tunze Turbelle Stream pump with 12000 liters (3170 gal) are operated with a
multi-controller in pulse mode. Total flow in the tank is approximately 26000
liters per hour (6868 gph). There is a spray bar integrated in the back of the
tank to prevent detritus from settling under the reef structure (constant flow).
Partial water changes:
6.25 percent weekly with Reverse Osmosis water.
Calcium addition, trace
elements and other supplementation:
Schuran Jetstream I, CO2
Calcium reactor in continuous operation (filled with coarse coral sand and
GroTech Mg Pro Granulate), Potassium iodide/fluoride, Iron, Amino acid, ZEObak
(bacteria solution), ZEOfood 7 (bacteria food), ZEOspur 2 and ZEOstart. About 3
teaspoons of Ca chloride are added every week to keep the Ca level.
95% of the corals in the system are SPS
(Acropora, Stylophora, Pocillopora, Anacropora and Montipora); 5% other sessile
invertebrates (Xenia, Sarcophyton, Tridacna and Goniopora). There are 30 small
to medium sized fish.
First, I would like to explain the ZEOvit
method and define all of it’s components in order to avoid any
The following components are manufactured by
ZEOvit (Mix of Zeoliths)
ZEObak (bacterial additive)
ZEOfood (food for bacteria)
The following requirements are also necessary
for the ZEOvit method to be successful:
Constant use of activated carbon
Optimization of nutrient addition
Addition of elements at low levels
The goal to be achieved:
The purpose of the system is to create a low
nutrient environment. Not only are we trying to reduce the measurable levels of
Nitrate (NO3) and Phosphate (PO4), we are also lowering
the levels of mineral concentrations like Calcium (Ca), Magnesium (Mg) and
Carbonate Hardness, (KH) while keeping the addition of trace elements to a
In the following section, I will address each
component of the ZEOvit system and give a brief description and add my own
ZEOvit (Mix of Zeoliths)
a group of naturally-occurring minerals that exist worldwide. Their chemical
composition can vary greatly and therefore exhibit different properties of
adsorption, ion exchange or molecular retention. Today’s modern industrial
applications require very specific properties and therefore, most of the
Zeoliths used are either modified natural zeoliths or completely synthetically
The ZEOvit proprietary mix of zeolites
as supplied by Korallen-Sucht
mix of Zeoliths consists of four different Zeoliths chosen because of their
ability to reduce certain toxins in a balanced way. The useful life of the mix
is limited and it has to be exchanged every 6-10 weeks depending on the tanks
bio-load. The exchange itself can be done in a single session.
through the filter material should be active and strong. The amount of Zeolit
material used is 1 liter per 400 liters of water. It is important not to exceed
the recommended amount. This could have a negative effect on SPS corals and
excessive overdose could lead to tissue necrosis and therefore, coral death.
approximately 3 liters of filter material for my system. It is rinsed well in
fresh water before use in order to flush out fine particles created by abrasion
during transportation. An initial cloudiness in the water during introduction of
new material is not harmful to any living organism in the tank and usually
disappears within one hour. In the beginning, I employed the material in my
external sump in mesh bags. The bags were laid out on light diffusers with the
dimensions of approximately 20cm x 50cm. The entire area had a flow of about
2500 liters per hour.
Typical ZEOvit "reactors"
Photos courtesy of CaptiveOceans
In January 2003, I modified the way I use the
filter material. This change had a very positive effect on the corals. The
material was taken from the sump into a ZEOvit filter equipped with an Aquabee
2000 l/hr pump. The filter was placed directly into the sump. Within just a few
days, I observed a change in corals placed in areas with lower light
intensities. The coral tissue brightened and colors became more intense. The
change allowed for more contact time of the water with the filter material.
months ago I started to clean and mix the filter material on a daily basis with
the help of the integrated mechanism in the filter. This is done during the dark
period by raising and lowering a rod about 15 times. The resulting mulm mixes
with the tank water. A few weeks later there was a color change and more
intensity in some corals. The brownish color of the shaded part of corals was
replaced by their natural color. Other corals displayed colors unseen until
then. However, the base color of the corals darkens because of this daily
cleaning of the material.
Some of the corals maintained with
the aid of ZEOvit.
I would like
to emphasize again at this point not to use any other Zeoliths. There are
virtually hundreds of different materials with this name. Each and every one has
its specific use and was designed or modified for it. Using a zeolith with the
wrong properties could damage or destroy all of your reef creatures!
solution contains several bacterial strains. It should be dosed for a period of
10-14 days after every exchange of Zeoliths. I primarily follow the recommend
dose of 1-2 drops per 100 liters (26 gallons) of tank water. My experience has
shown that frequent excessive dosing can lead to tissue loss in certain types of
Acropora. Acropora turmida seems to be especially vulnerable. I assume
that these types of bacteria have the properties to convert nitrite (NO2),
nitrate (NO3) and phosphate (PO4) in a form where it can
be skimmed by the protein skimmer and therefore be removed from the system. This
is the reason why I sometimes dose this solution outside of the recommendation.
The result can be seen in the increased concentrated adsorbent in the protein
skimmer the days following.
Bacteria Food (ZEOfood 7)
substance is also delivered in liquid form and dosed in combination with the
bacteria. The recommended dose is 1-2 drops per 100 liters (26 gallons) of tank
water. When used with fresh Zeoliths, dosing is done daily together with the
bacteria for a period of a few days. After that dosing, a few drops are
administered every 4-7 days based on my observations. The manufacturer of this
product states that this food has a positive effect on reproduction of the dosed
bacteria. In addition, this supplement contains various elements that aid in
reduction of nitrate via skimming. It also provides compounds beneficial for
growth and color enhancement in SPS corals in a nutrient poor environment.
However, success can only be achieved if the above-mentioned conditions and
parameters are met.
, recently improved this supplement so that even with higher dosing, SPS tissue
will not darken noticeably. This is in direct correlation with the density of
zooxanthellae in coral tissue. Currently, the manufacturer markets this product
In summary, with the use of the three mentioned
elements, it is possible to reach near-natural levels of compounds measurable by
aquarists. However, near natural water conditions are not enough to achieve the
desired growth rates as well as promotion of intense colors. Some secondary
conditions are also required which will be described below.
earlier, the basis of this method relies on export of harmful substances through
skimming. With this in mind, it is virtually impossible to choose a skimmer that
is too large. Continuous use and frequent cleaning should be done in order to
keep the skimmer performing at its maximum level. I achieved better results when
the skimmer was adjusted to not produce too much concentrated skimmate. The
manufacturer recommends not using ozone or UV sterilizers so that bacteria and
elements added to the system are not destroyed. This makes sense to me, and for
that reason I do not use any of these devices.
the reef structure, I made sure to erect a “reef pile” right below each of the
three metal halides. These “reef piles” reach to about 15 - 20 cm (6 – 8 inches)
below the water surface directly below the 250 W HQI bulbs. Doing this created
areas of high intensity lighting providing optimum conditions for SPS that
originated from shallow water areas. I observed that fragments placed in the
middle of the tank displayed less intense colors than the mother colonies at the
top of the tank. Both the intensity, as well as the light spectrum play an
important role in coloring of the corals.
Continuous Use of Activated Carbon
positive results are achieved by continuously using high-quality activated
carbon for filtering. The company
recommends continuous use of 1 liter of activated carbon per 1000 liters (264
gallons) in the sump. I use 1 liter of activated carbon that is exchanged every
30 days. It is important to keep an eye on the quality of the carbon in order to
avoid introduction of harmful substances that can accumulate in the tank over
time. It is possible to maintain crystal clear water, which assures unobstructed
light intensity and spectrum from the light source. It is beneficial to knead
the carbon every couple of days. This prevents channels from forming and
exposure of new surface areas for the water to reach. I question the use of
activated carbon in a closed canister filter since it also removes beneficial
elements. Carbon containing PO4 should never be used. Test the carbon
by placing it in reverse osmosis water for a period of 1 hour. Pour the water
through a coffee filter and measure the level of PO4 in the water
sample. Allowing the carbon to sit in RO water for 1-2 days can also reduce the
release of PO4 by carbon.
Optimization of Nutrient Introduction
the goal of the system to reach a low nutrient environment, it is necessary to
limit introduction of nutrients with top-off water, and to keep feeding to a
minimum. There are several ways to do this. I decided on removal of dissolved
solids by means of a reverse osmosis system for water changes and top off water
since this was the easiest way for me. I added a deionization unit after the RO
unit. Another source of nutrients comes from fishes. Their fecal matter, as well
as uneaten food adds to accumulation of nutrients in the water. I feed small
portions with the pumps turned off to avoid food from drifting into the
decoration. This limits the resulting decomposition process of nitrite (NO2),
nitrate (NO3), and phosphate (PO4). The amount and type of
fishes should be adapted to the type and size of the system.
Addition of Elements in Small Amounts
An assortment of additives and
supplements intended for use with the ZEOvit system
Photo Courtesy of CaptiveCceans
nutrients, of course, also apply to the addition of elements. I advise against
high amounts of additives in this environment, since problems will occur sooner
or later. I attribute these problems to the slow but steady accumulation of
unused substances. In this case, less is often more. Many of the added elements
have toxic effects on the animals if they reach certain levels. Therefore, they
bring more disadvantage than advantage. This is the point that requires some
kind of change in the train-of-thought with this system. Regular addition of
elements in very small amounts and scheduled water changes are enough to avoid
deficiencies in the corals. It is impossible to recommend specific amounts since
every tank is different. Differences in equipment and stocking of the tank lead
to a high degree of individuality. The observation skills of the person taking
care of the corals are very important. One must keep in mind that additions in
this environment have delayed reactions of 2-3 days.
This fact is
very important when adding anything to the tank. Here is the technique I use if
I dose an element of which I do not know the reaction.
<Editors' note: We always advise that you test for any additive that you wish to
use!> I carefully dose once and wait a few days to observe how SPS
corals react. A very helpful indicator is coral coloration. The coral tissue
should be light and colors should be intense. Provided that measurable
parameters of nitrate (NO3) and phosphate (PO4) are
consistently at low levels, any darkening of tissues and disappearance of
coloring is always an indication of over dose. In my opinion, this is a much
better indicator than the questionable results of many test kits. Sometimes the
visual observation can lead to great differences in concentration readings due
to the subjective interferences required in these test kits.
As long as
parasites are not an issue, subdued colors and dark or brown tissue is in most
cases are the result of high nutrients. It can be assumed that either nitrate
(NO3) or phosphate (PO4) is present or too many other
elements are available.
I have learned from my own experience that constant and daily dosing of elements
can have negative effects on coral coloring. I do not have a factual
explanation, but I assume that this reduced color intensity stems from constant
availability of certain elements. My dosing regimen of different elements is
conducted on an alternating weekly basis on a non-regular schedule.
dose the following elements:
10 - 11 ml every 14 days
10-20 drops weekly
10-15 drops weekly
10-20 drops weekly
5ml twice a week
above-mentioned amounts depend on the SPS colors and may vary.
are some reactions that can be observed in my tank when the above-mentioned
elements are added.
Elements Concentrate (ZEOspur 2)
This is a new
product, which has only been on the market for a short period of time. I have
been using it in my tank for 9 months. Its affect can be seen 1-2 days after
addition to the tank. The coral tissue brightens up and brown color is reduced,
making the natural coral color more apparent. This is the result of a reduced
amount of zooxanthellae, and therefore produces better display of the corals’
natural color. The first addition led to slightly reduced colors but adjusted
itself fairly quickly. I was able to observe a constant color improvement after
each addition. This gain in color seems to have established itself at its peak.
ZEOspur 2 has to be dosed exactly as recommended. That means 1 ml per 100 liters
(26 gallons) should be dosed all at once every 10 - 14 days. I would absolutely
recommend not to over dose this supplement. It is also important
to dose the entire amount
at once. Reducing the amount and dosing the sum over two days
will not work. It takes a bit of experimenting in the beginning to figure out
the correct dosing quantity for each individual tank. I would not recommend
dosing more than 20% over the recommended amount. I suggest to increase the
quantity by 10% dosed a few days later if the recommended amount is without
effect. The recommendation is based on the total net volume of the tank
including sump, etc.
Potassium Iodide Concentrate
I have noticed that the addition of this
supplement leads to improved blue colors in SPS. In contrast to PVP iodide or
Lugol's Iodide solution, there is no tissue darkening as long as the amount is
appropriate. Another positive effect can be seen in Xenia, with better growth
and faster pulsing frequency.
of iron primarily affects the green color formation. This element has to be
treated with some caution. Iron is known to promote the growth of algae as well.
You can see the same result in the density of zooxanthellae in coral tissue.
Darkening of tissue suggests that too much iron is being added.
observations have shown that the availability of different amino acids primarily
aids in growth, as well as coloring of red and pink SPS. I have also noticed
better polyp expansion. Too much addition will
lead to darkening coral tissue.
manufacturer states that this concentrate serves as a food source for certain
bacteria cultures responsible for breakdown of nitrate and phosphate. Within
just a few days of first introducing this solution, I noticed that SPS tissue
started to become lighter. This condition was maintained with the addition of
this concentrate. Colors in SPS corals became more intense. The addition also
seemed to have a positive effect in the yellow colored Acroporas. I attribute
this to reduced phosphate and nitrate levels, which leads to reduced density of
zooxanthellae. It is unclear if SPS corals utilize any elements of this
supplement. Furthermore, as mentioned earlier, I also add infrequently bacteria
food, which contains other elements, such as vitamins. In my own observations,
this also has shown positive effects on coral colors.
I hope I was
able to convey a certain sense for each of the individual elements. The
difference between positive and negative effects is very narrow and is up to the
user to adjust the amounts based on their own observations for their own system.
Sometimes the mistake is made that elements are added if colors get lighter.
Many times the opposite would be the correct measure to optimize colors.
I do not add
strontium to my system, since I have not been able to see any advantages. If
strontium is available, this element will be used in SPS corals to build its
skeleton just like calcium. High amounts of strontium can lead to less stable
and, therefore, more brittle skeletons.
Parallel to a
low nutrient environment, you will also have to adjust calcium (Ca), magnesium
(Mg) and carbonate hardness (KH) to natural levels. The following concentrations
have shown to work for me:
concentrations show no advantage. Neither growth nor coloring in SPS corals can
be positively affected. However, if any of the mentioned parameters deviates too
far, the result can quickly become negative in the established environment. If
you compare these concentrations with the average values of reefs in nature, you
will notice that conditions are very similar. I have also observed that these
values have to remain as stable as possible in this low nutrient environment.
show tissue recession, many times the reason can be found in the above-mentioned
parameters. After bringing levels back to normal, tissue loss usually stops
within a few days.
it is important to reach a balanced state in the above-mentioned parameters. If
one of the parameters fluctuates too much, it will have a noticeable negative
affect on the SPS coral. The best control parameter next to available water
tests is the ability of the observer to notice changes. At this point, I would
like to offer my advice regarding exaggerated responses to “measurable”
problems. Many times it is a test error or the result of expired or
inappropriately-stored test kits. If I notice that one of the parameters is
noticeably off, I test the result again,usually with a new test kit- before I
start any measures. If the original test result proves to be correct, I slowly
implement the appropriate steps to account for the deviation during the next few
must be taken with the reading of your salinity. I was able to use three
different test methods (specific gravity meter, refractometer and conductivity
meter) for 5 individual tests. I noticed significant deviations. The test
results varied from 1.021 to 1.026. Starting at a salinity of 1.0255 (specific
gravity) many Seriatopora and Stylophora can be very sensitive and may show a
definite tissue and color loss. Reduced color intensity, as well as slower
growth can be seen in all SPS corals at this salinity level
the age of the system and the current nutrient levels, it can take up to 6
months for this system to show results. After that, however, success should show
fairly quickly and conditions can be maintained if the above-mentioned steps are
with this method has shown that SPS corals are more sensitive to calcium and
magnesium deficiencies in this low nutrient environment. Each of the values
should be in the above-mentioned range. I also want to annotate that the test
kit readings are often very different and wrong. If I use a new test kit, I
first check it with natural seawater that I collected from a coral import. Also,
the salinity level is important. A low salinity level is more tolerable than
high salinity. An indication of deviation of these parameters is the slow but
steady tissue recession on the base of the SPS coral. If this is the case, the
parameters should be properly checked and adjusted if necessary.
opinion, patience, care, observation, and the ability of reserved addition of
elements next to the “common” technical equipment are necessary to get the
desired results with this method.