Hi,
I have one of these 6 feet CC skimmers. They are very nice (in performance) and they do a pretty good job. I still have to run carbon (i.e. it is not that good), but the tank isn't as yellow as it used to be.
http://www.hawkfish.org/snailman/snailmandiy.htm
I have a 4" diameter by 6 feet one on my 90 gallon. It is driven by a TetraTec Deep DW96-2 air pump -- a bit loud, but it is solid pump. Cost is about $200 for the whole thing - $130 for the air pump. For a better air pump, you'll have to get one of those nasty Hagen "The Pump". The only problem I have with this skimmer is its size...it doesn't fit underneath the stand.
- Victor.