In spite of what many people assume, corals do not come from a stable, calm and never changing environment. They come from a temp swinging, salinity swinging and at times very violent environment. They deal with this as well as predation, storms, physical damage from fish, powerful wave action and currents, etc etc. The chemistry is fairly stable and that is what is most important. Other than that, their environment is at times harsh one.
+1... i was one of those at the beggining and have found corals are in general TOUGH not delicate suckers!
Just don't let ALK, CAL, MG or salinity sway quickly!