In my experience with the herbie setup I can't ever tune the gate valve finely enough to EXACTLY match the pumps output. The output also does change I suppose very slowly as it gets dirty. Either way what I have done is get it as close as possible so that the very slow creep is up and the emergency drain always has a very small amount just seeping down it. Bubble free, silent and like you said I have both my main pipe and my emergency very high. The overflow skims but drops about 1/2" into the box.
|