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My
mbuna tank (see
photo above) has
a capacity of 500 liters - 125 gals (measuring
150x50x65 cm). It is filtered by two external canister filters and
two internal sponge filters (a total of 3600 L/h), and lighted by
7x40 W fluorescent tubes of various brands and colors. I always use
two Penn Plax Ultra Tri-lux tubes and the others are either Penn
Plax Tri-Lux or normal greenhouse lamps (PHILIPS Aquarelle or OSRAM
Flora) to reduce the cost. The lamps are changed once every year,
not all together but one every month. The average lighting
is more than 0,5 Watts per liter. UV sterilization is also in line
(two 8-watt units from Aquanetics) to the external filters and stay
on for 8 hours daily. I also use a CO2 injection system, which
consists of a 2.5 Kg (5 lbs.) CO2 canister, regulator and silicon
tubing (the normal airline may lose as much as 50% of the carbon
dioxide injected). There is a bubble counter on this system and a
CO2 diffuser, which was later removed because I found a more
effective way to increase the dissolution of dioxide in the water. I
drilled a hole in the intake of the external filter and attached the
end of the silicon tube connected to the CO2 cylinder. Thus, the
carbon dioxide is forced to travel in the water stream for many
meters, get in the canister where it is dissolved and then is
returned in the tank. The gas is dissolved so efficiently that you
can barely see any bubbles coming out of the filter outlet. There is
also enriched gravel and continuous pH monitoring. Typical
water parameters are Temp 26-30C (the latter in the summer
when four ventilators are pointed parallel to the water surface to
increase water evaporation and cool the tank a bit), pH 8.3 (before
the injection), GH 10° and KH 14°. Maintenance routines
include a 50% water change every week, and regular additives such as
liquid plant fertilizer, aquarium salt, baking soda, and others. Among
the fish species are Melanochromis
auratus, Melanochromis chipokae, Melanochromis johanni, Maylandia
lombardoi, Cynotilapia mbamba, Labidochromis caeruleus, Akanthopsis
choirorynchus and
Pterigoplichthys multiradiatus.
Lately, a trio of Haplochromis nyererei
was donated by the co-author of this site, Francesco. Plants
include Echinodorus bleheri,
Anubia barteri, Anubia nana, Cryptocorine willissii
and Hygrophila corymbosa.
Needless to say, there have been quite a few other species which
were initially tried but they didn't make it, either because of
mbuna consumption (Egeria densa)
or the water conditions. I feel that, despite the carbon dioxide
injection and the fertilizer, most plants simply can't cope with the
high mineral content of the water and the high pH. Amongst the ones
which do, you must choose the ones which are not consumed on the
spot by the mbuna or grow fast enough to outrun them. Once you solve
these problems you can focus on aquascaping and pot the plants in an
aesthetically pleasing way.
I
think that the best advice with this sort
of tank would be to take care of the fish and not the plants - this
is rule number one and should be followed strictly. I do my CO2
injections with the eye on the pH meter. The starting pH is 8.2-8,3,
the KH of the tank is 14° (which means a very big capacity for CO2
without dramatic changes in the pH) and I wait till the pH drops to
7,6 over a four hour period. Then I stop the injection and let the
pH come back to 8.2 (it takes another 8 hours to do so). This is the
normal day cycle. I always have heavy aeration with the internal
filters pointing at the surface, even during the actual injection of
CO2. When the
lights are turned off an air pump goes on until the next day cycle.
This way, any remaining CO2 is
removed from the tank during the night. In any case, CO2
is absolutely essential for this kind of aquarium but you should be
very careful not to overdo it. African cichlids come from a habitat
where dissolved CO2
is very low and won't tolerate very high concentrations of this gas
in their water. My approach doesn't seem to stress them (at least
the species I keep) and it also helps the plants to grow at very
good rates.
When
the tank was initially started I used a
mix of teralite / gravel 1:3. Actually it took 35 Kg of teralite and
100 Kg of gravel to get the 4 inch (10 cm) substrate I wanted. I
used some plant pellet fertilizer buried next to the roots (Tetra
Crypto tablets) for the first 6 months after setup and then stopped
it. The plants in the tank will not thrive. They will have a steady
growth, which is enough to compensate for the consumption of leaves
by the mbuna. Mbuna when fed correctly should always starve in order
to be active, spawn and display their beautiful intense colors. The
recommended feeding is small quantities every other day. This means
that in the "non feeding" day, almost all mbunas will
attack algae and plants. They will eat Egeria
densa (except the top of it, which is
regularly replanted when the rest of the plant is consumed), will
eat Amazon swordplants
(almost every mbuna will nibble on it, therefore this plant is not
to be kept in such a tank) , Vallisneria
gigantea (yes, they will eat that, too,
even the runners), Hygrophila corymbosa
(which grows much quicker than mbuna can consume). They will even
nibble on anubias (to a far lesser degree). The only plants they
will not attack are Cryptocorine
and Nymphaea lotus.
If
such a tank is to be aesthetically pleasing and safe for the fish,
one needs to spend much more time on it than with a regular tank.
You must remove eaten leaves at least twice per week and clean
filter intakes every other day. Strong filtration is essential which
means at least 4-5 times the water volume per hour. A much stronger
filtration rate (10-12 times the water volume) is highly recommended
if carbon dioxide injection is to be introduced. Better safe than
sorry. If you are not going to use the extra - sophisticated (and
rather expensive) pH controlled CO2 delivery systems you should also
pay attention to the manometer of the gas cylinder. When the
pressure in the cylinder drops significantly, you should get your
cylinder refilled. Do not try to use all the gas because when the
pressure gets very low in the cylinders, most manometers tend to
release all the gas at once and it doesn't take long to lose all the
fish from suffocation. Once, I forgot to check the manometer for
over a month and then, when I came back home, I had to manually stir
the water for 30 minutes to get the gas out of it. Unfortunately,
one of the mbuna didn't make it while all the others remained
lethargic at the bottom for another 3 hours. It goes without saying
that an established biological filtration is of outmost importance.
All plants should be planted with their pots (if supplied) or else
secure them in place with rocks, big enough for the mbuna. It is
even better to create "rock pots" fill them with gravel
and whatever else you want to add (teralite, laterite etc) and then
add the plant. It is a very good thing if you can decorate your tank
before adding the fish. If you can allow some time for the plants to
establish it will pay off later since the growth will be enough to
compensate for eating. Another point is to use fast growing plants,
able to survive and grow (not thrive) in a pH around 8 and a GH
around 10°. The exception is anubias, which are not eaten so they
will grow in peace, they will even produce flowers every now and
then. Intense photosynthesis will be observed for about 4 hours (see
photo below).
Continued
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