Let me see how things look if you want to put in the Ultrasieve MIDI. I need to redraw that unit as I didn't make the stencil for it when I was building my own pond
Do note that the MIDI is much shorter. You will have to find a way to elevate it off the base.
Gotta look around for the 200micro screen. Maybe ask the folk in Koiphen if they can point you somewhere. The MIDI is less popular as it moves less water than its big brother so the parts are a bit harder to find online. 12000lph is still plenty for an semi indoor pond.