On occasion I'll loose an inch of montipora to my colony but the dead area quickly becomes grown over again. The only circumstance where you'd really need to worry is with tiny frags placed adjacent to the colony or toppled coral landing on it. But that basically goes for any coral.
The conditions mine is under are: 250W Phoenix 14K DE, moderate flow, 78 F, 1.025, pH 8.1-7.8, Ca 450ppm, Alk 10 DKH, Mg 1400ppm.
