alrighty then matt, i will arrange something with Shipley then...thanks for your interest.
Shipley, it should fit nicely in your 20...thats what I was using it in in the past. It does require a roughly 3in square area in one corner of the tank so you may want to measure and see if you have room for that. of the 18in of depth only about 12in of the skimmer is in the water so that leaves about 6 in below for a little LR or an open sand area in your tank
anyway...shoot me an e-mail and we can figure it all out.