I modded mine when I had it, I just cut back the small acrylic tube inside that the 'tornado' comes out of.
You want to increase the airflow, so there isnt much of a tornado. It will also limit the air bubbles going into the tank. This will make it noiser and start skimming really soon.
it is a nice skimmer to some extent, but it really takes a lot of work to get running good. And once its running needs often tuning.
I bought my ASM G-2... I wont look back.
maintenance, besides cleaning the collection cup... which can get discusting in a day, or less! Even with my low bio- load.
oh well.. I am getting more fish in tomorrow, (Pygmy Angel, Blenny, Royal Gramma, along with many... many inverts 100 micro blue legs, some ricordea etc. all from reeftopia.com)