What can Cause Bleaching in BTA's?

[Reef enthusiasm]

Can some experinced people just chime in on what causes it, preventions, and/or solutions?
(My Nem is fine, but I'm just trying to be preemptive here, in case it ever does)

 

[phender]

Chances in any condition, especially if it happens quickly, will cause bleaching.

I had a friend that didn't have air conditioning in his house or a chiller. His BTAs (he had about 10 small clones in the same tank) bleached every Summer as the water temps got above 82 degrees. When the temps went down again, they usually colored up again.