Calcium reactors are very useful for the propagation
of SPS corals and tridacnid clams. As
these animals grow they use calcium and alkalinity from the water to form
skeletons and shells made from calcium. The growth of these animals requires
high levels of both calcium and alkalinity and with the use of a calcium
reactor these levels can be easily maintained. Calcium reactors, when
set up correctly, will maintain both calcium and alkalinity in the correct
ratio making it unnecessary for the addition of these types of additives
for the proper growth of these organisms.
Calcium reactors use a media made of calcium carbonate (CaCO3) to provide
calcium and alkalinity to the aquarium. This process is achieved by running
aquarium water through the reactor which passes through the reactor media
also which is then returned to the aquarium as effluent. The aquarium
water in the calcium reactor is also injected with CO2, which causes the
pH of the water in the calcium reactor to be reduced. Ideally the pH of
the water in the calcium reactor should be between a pH of 6.8 and 6.5.
The slightly acidic water will slowly dissolve the calcium carbonate media
which in turn will release calcium and alkalinity into the water. Depending
on how large the bio load of the aquaria, it will be necessary to adjust
either the amount of CO2 or the effluent rate. When the
effluent is introduced back into the aquarium at the appropriate rate
and pH, it will maintain the necessary calcium and alkalinity levels of
the aquarium.
Though calcium reactors will maintain stable calcium and alkalinity
levels without the daily addition of additives, reactors they do come
at a cost. Calcium reactors have a very high start up investment. Not
only will the cost of the reactor be incurred but a CO2 cylinder, regulator
and pH controller or monitor as well. The total of the calcium reactor
and all peripheral equipment can range between $475 and $575. Yearly operational
costs will be dependent upon the aquaria and will be a combination of
refilling a CO2 cylinder every 4-6 months (~$13) and also refilling the
calcium reactor with new media every 4-6 months (~$10- $30). Cost is not
the only factor to consider, calcium reactors will also lower the overall
pH of the aquarium. Most aquariums that utilize calcium reactors have
pH of 7.9 to 8.2.
Calcium reactors and the equipment needed to run them have a very high
initial cost. The cost of a calcium reactor may not seem to justify the
purchase. However over time the cost of two part additives to keep up
with the high calcium and alkalinity demands of SPS coral and clam aquariums
can be quite expensive making the cost of the calcium reactor less shocking.
A calcium reactor not only provides the necessary supplements for ones
aquarium but also provides the aquarist with more time to watch aquarium
rather than dosing calcium and alkalinity supplements.