Acroholic;505550 wrote: Jeff,
I think the acrylic cylinder under the taller of the red acrylic pieces is a bubble tube. Water enters the tube and the majority of the bubbles pop inside there. Remember that Marc Levenson used something similar in his wet drys.
I think the middle parts of the wet/dry is a water pathway.
Water enters thru the gray pvc pipe that goes down into the acrylic cylinder. It then bubbles over the cylinder top and fills the rest of the chamber. Is there a pathway for it to spill onto the drilled red acrylic square, because that looks like a small drip tray? If you notice below the small drilled red piece there are a couple acrylic strips. They are probably there to support a small piece of cut eggcrate about the same L x W of the drilled red piece. You layer your chemical media on this eggcrate and the water from the red drip plate flows the water thru the media and then it returns to the return part of the filter.
The larger PVC female threaded fitting is an optional return for a skimmer, or a cleanout port. The gray PVC pipe going into the acrylic tube is meant to be fed via a small internal powerhead or a tee off the intake pipe from the tank.