..noticed someone mentioning that they didnt find the gunk to move into the "overflow cap" that easily...i have read that the reason the foam is pushed up through the top is because of the temperature difference that is above the water level...therefore im assuming that the more drastic this difference is would equate to the speed of the foam moving up into the overflow at a higher rate...just a thought...its all very interesting..
also..
www.aquaticeco.com is the best..i am thinking of becoming an agent for them and that means cheaper shipping..they sell all the acrylic tubing there as well as the industries best quality air diffusers that are made from heat bonded silica..the model that i think woudl work best is the AS40 ..i will be using these on the skimmer that i am making in the near future..peace