Read the other post on it and you will see that a very few people have had any luck with it with most people not being able to get it to work properly.
I have owned two, and the LFS store has stop carrying them because of all the complaints they had. They skim very little and that is when you have it set in there just right, and when it is not, then the cup fills up with water. I had my uncle(who has set up serveral protein skimmers) try to get it to work and after a couple of weeks could not get it to do much, if anything. The LFS owner didnt believe so he set it up to prove me wrong and after a week or so; he gave up. With that and several other complaints he stop selling it. One person on another site had it kill everything in there tank after a few hours. I have read all the post and one time gave a positive post on it after spending hours of getting it to work right but it didnt last long. Once you water level drops just a little it stops. Too much work for this thing. I have less nitrates by using Purigen than that protien skimmer.