Overflow water level?

[Euclid]

So I've got this funky valve on my return pump that lets X% of the water back into the sump. This is to prevent it from pumping too much water into the tank.

My newb question is this, where should the water level in my overflow be?

http://i14.tinypic.com/5yb9xfp.jpg

[caferacermike]

At about the 2 on your scale. If it is to high, that cap has way to small a hole in it or your weird valving needs adjustment. Open the valve on the return pumps recirc line more to lower the water line in the tank.

[Euclid]

Thanks Mike!
Do you think I should rewire this thing with the Mag 9.5 and then reduce it's flow to save water?

[caferacermike]

I do think the Mag 12 is a bit much for the way the system is designed. The system is running well and some thought did go into it. I might be able to help you re-plumb it so that it is a little more efficient. I'd put the recirculation side of the pump back into the skimmer section. That way it might go through the skimmer a few more times rather than just recirc back at the pump. Of course running the Mag 9.5 will reduce the need for a recirculation loop and probably lower the temp of the tank as well since Mag's are not efficient pumps.