The orange area would be your sponge. Water enters there and travels through a 1/2 inch pvc with an end cap. Holes drilled in it would allow the water to escape out through your media into the vertical tube. Holes in the vertical 1/2 inch pvc would allow water to enter the pick up tube, again through your media. No need to glue any joints so it could be easily taken apart to clean and reassembled.
You could further subdivide the media with a plastic barrier around the 1/2 inch pvc and the 2 inch pvc.
2, 90 degree 2 inch, 4, 2 inch end caps, 4, 1/2 inch end caps is all you need.
Still would need a means of connecting the power heads to the 1/2 inch pvc.
Problem with linear flow, from one end to the other, the closet end to the intake becomes the work horse, this way all of the media will share the load.