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2. Theory
The equilibrium between calcium and carbonic acid in a saltwater aquarium is destroyed due to the
biological activity of the animals. For the construction of their calcareous skeletons they take
calciumcarbonate out of the water. As a result, it comes to a lack of calcium and an increase of the
pH value.
The Aqua Medic
Calciumreactor
is a module for adjusting the natural equilibrium between calcium
and carbonic acid in the aquarium. It is filled with Hydrocarbonate, a highly purified
calciumcarbonate. Because this calciumcarbonate is not soluble at pH values common in seawater
tanks, it is necessary to blow carbonic acid into the reactor. This results in a local drop of the pH
value and simultaneously to the dissolving of calciumbicarbonate.
To avoid an overdosage, the addition of carbonic acid can be controlled by using a pH Controller or
pH-Computer. This method does not change the pH value of the aquarium water.
Chemical reaction
CaCO + CO
2
+ H
2
O -----> Ca
2+
+ 2HCO
3
Calciumcar Carbonic acid + Water ------> Calciumbicarbonate
Calciumbicarbonate is easily soluble. It can be directly taken up by animals and plants and
integrated into their skeletons. By doing this, calciumbicarbonate is changed back to
calciumcarbonate. During this back reaction, CO
2
is released which is used by Zooxanthellae for
photosynthesis.
3. Working principle
The
Calciumreactor is supplied with water from the top. The flow rate should be adjusted that way
that the ph-value doesn’t exceed 8.3 during the day and doesn’t drop below 7.8 at night. The flow
rate can be adjusted exactly by the dosing pump SP 3000 (included, max. 3 l/h) and a timer (not
included in shipment). The circulation pump placed in the top of the reactor circulates the water
internally. The CO
2
is connected to the injection port on top of the reactor. The pump sucks on CO
2
.
Through the rotation of the patented Aqua Medic mesh wheel, the CO
2
will be completely dissolved
in the water. Then the CO
2
enriched water is pumped below the Hydrocarbonate and finally
circulated. Thereby, calciumbicarbonate is extracted from the Hydrocarbonate. This is exactly the
combination which corals need for their growth.
The outflow is located in the top of the filter. From there, the water flows into the aquarium or back
into the filter tank. The carbonic acid can be added from a pressure bottle.
4. Set-up
This version of the
Calciumreactor
is a closed system that can be operated without a cabinet
filter.
The reactor can be installed below the aquarium from where the water can flow into a filter
chamber or back into the aquarium.
IMPORTANT: Never completely close inlet and outlet as excess pressure due to carbon
dioxide supply may arise!
The inflowing water quantity has to be adjusted in a way that approx. 1 – 3 l/h flow through the 6
mm pipe into the reactor. The adjustment and the quantity of CO
2
depends on the aquarium size
and the calcium requirements of the animals.
5. Starting
The Calciumreactor has to be closed by eight clamps that are pushed on from the side. Before
starting the unit, please check that the sealing is inserted correctly and all clamps are tightened.