What would make a skimmer freak at night?

Prior to new skimmer, old skimmer died and tank went south a bit - algae broke out and a couple hard corals stopped growing and lost color.

I put in a new rocking Turboflotor skimmer and dialed it in. Things looked good again other than the corals that lost color. Then those corals - Insignis and Cali Tort - started bleaching - RTN - this make the skimmer go wacko and fill up every night.

I fragged them, kept what I could and tossed the rest, yet everynight my skimmer is still filling up. Weird thing is, during the day it's mellow... but when the lights go off, it starts freaking. What's going on?

 

Is something spawning or giving off nematocysts at night?

 

Not that I know of.
I would like to blame this on my prolific Cerith snails, but I have no idea.
I added the optional extension to the skimmer tube to try to mellow it out.

 

Well it looks like the tube extension did the trick last night. Hopefully it will hold out. I get nice dry foam now and dark skimmate.

That was really cool that Aqua Medic provided the extension. First morning in a week I didn't have to drain a pint from the collection cup. 8)

EDIT - If you have the Turboflotor Multi and decide to put the extension on like me, don't forget to take off the o-ring from the smaller extension and use it on the longer one. I forgot and noticed water collecting on the top edge. Luckily, I noticed it!