Steve, I'm struggling with the same issue. I think 4" flow is 3800 gal/hr. But I don't know if that's max flow pressurized or gravity fed (guess gravity also depends on how much PE is behind it).
Gravity fed bottom drains are what I'm planning for, but I have the same fear as Steve, that the poop will settle and the water'll just flow over it. Someone answer Steve first, and then...
2 4" bottom intakes
1 4" mid-level intake (can adjust flow on this one)
Gravity fed to settlement tank, with 4500 gal/hr exiting the settlement tank.
Can someone answer without fluid dynamics equations?
Thx a lot. Much stomach churning over this.