Right then. So as previously discussed the original design had two outflows:Love a good close up of each section of the sump with an overview of all of it. Been running a fair few weeks so would be good
You’ll just have to use your imagination @Chris Tinker and erase one of the outlets. However this is pretty much the setup around the back as it is now. One difference would be that of the two intakes in the overflow box, you cut a piece of PVC pipe and use this as a stand pipe/overflow (for obvious reasons it must be cut to the maximum height you would want the display to be at before the overflow comes into use).
You can run this like a herbie overflow but from experience this isn’t worth it. With the lid on you a) can’t hear it if you adjust the ball valve correctly and b) the drop of the water causes minimal gassing off and the lid (not on in this pic) seals the unit up reasonably well.