Hi! I have super skimmer too and i also have the same problem.. (i've had floods in my apt and its a pain..) From my experience, the collection cup only overflows because of the level of water the pump is in. the further down the pump is from the surface of the water, the higer the level in the skimmer (and this is normally when it overflows
). I usually try to keep the pump about an inch under the surface. are you using it as HOB? or in sump? if you go to coralife's website, there's a forum for the super skimmer where u can find the proper water level and etc. there's also a big thread on reef central. is the red knob also leaking on your unit? I think it's a good skimmer, it's just finicky. hope it helps..
wally