Exposing SPS during water change

[Reef Pilot]

I have a new SPS (Purple Cross) coral that I placed on top of my highest live rock, in order to maximize its lighting intensity. However, I noticed that during a water change, part of it is exposed for a period of time (about 15 minutes) until I can refill the tank with the new water.

Is this a problem? Will the coral suffer? One option is to bath the exposed coral manually with water every few minutes while it is exposed.