I have a Reef Octopus I bought from bulkreefsupply.com. It runs my 75 with capacity to spare. It is a recirculating needle wheel with a Sicce (sp?) pump. The bubble quality and quantity are good enough that I haven't bothered with any mods. I've had it a year and had no problems. I'm not sure of the model, but it is a little over 6" ID X 26" with large plumbing. I think its rated for 150 gallons. I run it with a Little Giant MD2 (500 GPH) and have the exaust over half closed to maintain the water level. I think it would handle a little over 800 GPH easily. I can make it produce any type of skimmate I want from light brown water to a dark almost black sludge. The drying tube and cup is very easy to clean which is good beause you'll have to clean it often.
The level adjustment was initially hard to tune, but it settled down and is now very easy and stable. It also tends to leak where the recirculation motor is plumbed unless great care is used when you assemble it. Micro-bubbles are a slight issue, but that is easy to overcome. The exaust plumbing is UPVC that does not fit with PC (40 or 80) or CPVC.
Otherwise, I have no complaints. Its a great skimmer for the money. A gate valve mod would make it better.