I'm going to try and make 2 more of these blank of plate I use on my Aqualine tanks for testing. If anyone is interested in one let me know. If I put a standard pipe tap threads in for a barb fitting that would be the easiest.
Let me know, I'll see if I can dig up some material.
If I ever get a 990 I'd want the pump and prefilter setup "outside" the tank.