|All quality salt mixes include the trace elements required by corals, fish, and invertebrates. These trace elements are regularly depleted by your aquarium inhabitants, protein skimming, and chemical filtration. Monthly water changes of 20% to 30% are recommended to replenish any elements which may have been exhausted. In a heavily-stocked reef aquarium, these elements are often depleted at a much faster rate, and should be replenished by using commercially available reef supplements. The trace elements of special concern for reef tanks include calcium, strontium, and iodine.
One important trace element is calcium, which is depleted very rapidly by both hard corals and the coralline algae in the system. Calcium also plays a crucial role in buffering your water. It should be replenished and maintained at 350ppm - 450 ppm using kalkwasser, calcium reactor, or a liquid calcium.
Strontium is utilized by both hard corals and invertebrates and should be maintained at a level of 8 ppm with the use of a liquid supplement.
Iodine is consumed by all aquarium inhabitants and should be maintained at 0.06 ppm with a liquid supplement.
All other major and minor trace elements should be maintained both through regular water changes, and with the use of a liquid supplement.
Trace elements can be overdosed into the aquarium, so be careful and monitor these levels with the appropriate test kit and keep and eye on the overall health of the aquarium.