Herbie sump ?
 

Has anyone tried running a line off a herbie drain to feed a fuge?
Using a ball valve to control the flow.
As in a design like this.
http://members.shaw.ca/kabong/herbsump.JPG

I have one of my drains plumbed like that so some flow is bypassed to a dedicated refugium and it doesn't act like a Herbie.

If you closed the valve completely all you would be doing is just send all your water to the fuge. To have your drain behave as a Herbie you would need to restrict the overall flow from the drain so you would need to valve both legs. Could see it being a little difficult to set up.

I don't mean to have the ball valve control the Herbie aspect of the drain.
It would still have the gate valve up above the branch off.

Yeah that should work...haven't tried it myself though

Yes, that looks like it would work.