The Acropora Corals prefer a high light level combined with a strong, intermittent water current within the aquarium. For continued good health, it will require the addition of supplemental calcium, strontium, and other trace elements to the water.
Small Polyped Stony corals (SPS) are characterized by their stony skeleton and very small polyps. They require very high light, good current, and excellent water conditions. The addition of calcium and
strontium is essential to their health. SPS corals are reproduced by fragmentation. When kept in good conditions these corals grow quite rapidly.
Trace elements typically get depleted by uptake by organisms and by other processes. Though the matter of trace element additions is currently in hot debate among reef aquarists, noted authors have made strong arguments that it is prudent to maintain trace elements at or near natural levels. Trace elements can be maintained in several ways. Some aquarists simply do regular partial water changes using fresh seawater (normally synthetic seawater is used), which helps to maintain proper ionic balance in the aquarium. Some authors have argued that regular feeding of an aquarium replenishes most trace elements adequately. However, many aquarists also make regular additions of trace element supplements. Iodine is generally considered to be important for some marine invertebrates and for certain red macroalgae. Iron is generally considered to be important for some corals (e.g. Tubipora sp.) and many of the marine plants such as turtle grass, macroalgae, and turf algae.
In reef tanks, which typically have high densities of calcifying organisms (e.g., coralline algae and stony corals, both of which create calcium carbonate (limestone) skeletons as they grow), proper levels of strontium are also very important. In fact, stony corals in the genus Acropora were considered to be impossible to keep in aquaria until their need for strontium was recognized. Many reef aquarists add strontium on a regular basis, using either a strontium chloride solution or a commercial trace element mix that includes strontium along with iodine and iron and a variety of other trace elements. Other aquarists depend upon release of strontium from their sandbeds as the sand gradually dissolves, or regular water changes as described above (the dosing of strontium is also in hot debate!)
This is a good one
http://www.advancedaquarist.com/issues/apr2002/chem.htm
All of the source are easly found on the net.If strontium is not good at all then why does every major reef suppliment manufacture make strontium
Hope this helps