check
www.savko.com for acrylic tube, it is relatively cheap, easy to get, and they will send you whatever you want. I see many issues with keeping a cinsistent water column height when using 2 foam risers, most of the issues with making a foam collection skimmer work revolve around keeping the column height steady and keeping the riser clean. Cleaning a 3" ID tube can be a bit of a hassel, 6" is MUCH easier. I'd also recommend that you add a quick release to your
riser tube to make cleaning easier.
HTH
