My tank just turned 1 this month

, and I'm planning to add a mushroom coral to the system. Since I only have a 65W
PC on my 37 gallon tank, I figure I should stick with hardy corals that do not need immense amounts of light.
Given a 65W
PC light and a tank which is 22" tall, how far from the light should I place the coral, or does it matter? Suggestions anyone?