I not a big fan of copy and paste but this read is pretty understandable I think.
The task of maintaining a balance of calcium and alkalinity is often a frustrating topic for many aquarists. Understanding how calcium and alkalinity are utilized goes a long way to tackling the problem and coming up with cures. We will give some basic background information and guidelines to follow to help you along in your quest to have the perfect reef aquarium.
Please also refer to our Calcium & Alkalinity articles.
How the Relationship Works ...
In previous articles we have already defined what calcium and alkalinity are and what uses them. Now we must define the relationship they have, how they work together, and how they balance. We also know that maintaining a balanced calcium and alkalinity creates a stable, growing environment, and reduces the need for daily testing.
Calcium and Alkalinity are supplied to reef aquaria in order to balance the losses caused by the formation of calcium carbonate (calcium and alkalinity combined). An example of this formation would be the skeletal growth of a coral. The reef aquarium uses carbonates and alkalinity at a ratio of 1 meg/l to 20ppm, respectively. Most aquarists choose a 1:1 dosing scheme of calcium and carbonates who"s end result is more than often a balanced chemistry.
Many aquarists turn to two part supplementation additives to handle there calcium and alkalinity needs. Where by equal amounts of each solution are added routinely to maintain calcium and alkalinity to proportionate values. More than often, for various reasons, one or other will fluctuate resulting in an imbalance.
Troubleshooting and repairing that imbalance is often misunderstood
Frequently the imbalance is caused by additive overdose. Often a calcium supplement is overdosed, forcing the precipitation of carbonates (alkalinity). The result is a high calcium value, but a lowered carbonate value (which in turn may affect pH). Or vice versa. A fix for this is to either: a) stop dosing the offending portion of the two part additive, or b) using a buffer to gradually raise the suppressed ion to its desired level.
Once the balance is restored, the two part additive may be continued as usual.
Imbalance is often caused by salt mixes during water changes. Salt manufacturers often leave certain elements at unacceptable levels for reef aquaria. Knowing the calcium and alkalinity of your salt mix will allow you to make calculations for what additives to add to counteract the potentially chemistry altering effects of a water change.
The use of tap water can also alter the levels of calcium alkalinity in your aquarium. More than often calcium and hardness fluctuate in tap water and cause undesirable fluctuations water chemistry, resulting in a less stable environment. Knowing the calcium and alkalinity of your tap water, or the use of reverse osmosis systems will help you take measures to ensure your waters stability.
Rapid addition of stony corals or rapid coral growth, may also cause fluctuations. In which case it is only a matter of determining the values of calcium and alkalinity, making chemical adjustments, and returning to the usual method of supplementation.
How do I maintain a constant calcium and alkalinity?
The answer to this is really uncertain. Knowing what causes drops and fluctuations helps you maintain your chemistry, but there are unfortunately no hard and stead fast rules to follow. Frequent monitoring of your aquariums water chemistry and the use of an appropriate calcium and alkalinity supplement will go a long way to achieving success!
There are a number of different calcium additives to choose from. If you have a large system, a more suitable approach to maintaining calcium and alkalinity would be the use of a calcium reactor (a mechanical device in which aragonite media is dissolved using CO2 gas to maintain alkalinity, calcium, and other minor trace elements in unison) or the use of kalkwasser (calcium hydroxide mixed with water). The use of Kalkwasser should be limited to experienced aquarists.
