Ok, well just watch it.. cuz it will over flow
Under "normal" conditions it will overflow nicely. But when something enters the tank that alters the surface tension, for example, those slime coat products. It will overflow like crazy.
It is talked about on RC in a few of the MCE600 threads.
Here is a link where Deltec even talks about it. though they don't mention that the overflow tube provided cannot handle it sometimes.
http://www.deltecaquariumsolutions.c...ariumSetup.htm
Its not a HUGE issue.. but I have come out to my tank a few times to see my floor covered in water from my MCE600 going wacko! Though now that I know about it I raise the collection cup after a water change. This happens with Kent salt for me. Not sure about the other salts out there.