It looks like the cage should do the trick! The water level depends on the design of the sump too, if I go for a similar design to yours with mostly submerged media (still waiting on a price for the pond matrix) then a higher water level will be ok. I was planning on trying to run a trickle tower, but with the low height coming out of the tank there just isn't enough vertical fall to do it unless its run off a seperate pump in the sump. I already have about 40L of bioballs and ~20kg of cheap ceramic noodles, but its probably money well spent investing in some quality media like Matrix...
Right, any more questions and I'll make my own thread!
Right, any more questions and I'll make my own thread!