Big Green Spots/ Coral Bleaching

[NickW]

I have a newer system(8months old) and along with coraline algae on the back of the tank I have big green spots alos showing up on the tank. Does anyone know why? should I worry?

Second, a roommate left a back door open at night about two weeks ago and my tank temp went down to 66 deg. F. and now some of my hard corals are bleaching, any one have an oponion on why please let me know?

 

[jetaero]

As for the green spots on the back of the tank... That could be green corraline? or a type of diatom. Algae is always normal in a reef.

As for the bleaching, if your tank temperature went all the way to 66F from say 80, that would cause a considerable amount of stress on the coral, so if only bleaching, I would say you are lucky.

-Josh-