my berlin h/o does a pretty good job, too!
my simple explaination to my wife and kids about what it does "it's kinda like a toilet for the fish tank". skimmers are great, helps to ensure the water quality. tacks, by the way, if your h/o begins to not produce the same amount of micro bubbles even after you adjust the venturi screw, it may need to have the venturi valve cleaned. i had to do mine a few days ago. voila! works like a champ again.