Thanks, Tim! I have to disagree with the aquaC recomendations; it's a little delicate because I don't want to sound like I'm pushing my skimmers on anyone. I had a EV120 on my 110, and I was pretty disappointed with it, in fact, that's part of the reason I decided to try my hand at making skimmers. Maybe the bigger aquaC skimmers work better.

Rather than try to push one brand of skimmer over another, I'd say that IMO the most important design considerations with skimmers are contact time (which is closely related to skimmer volume) and consistency of foam generation with changing organic loads in the water. Other than a huge airstone skimmer, I feel that the skimmers that best achieve these characteristics are large beckett skimmers driven by a high quality pressure rated pump. To me, aquaC skimmers are simply too small, with very little space in the tube for consistent, strong foam production with little turbulence, which tends to disrupt the foam stability. Also, the recommended pumps for aquaC (mag5 on the EV120) simply cannot maintain a steady stream of water speed through the injector as the load increases. What happens is, as the organics in the water increase, more foam is produced at the injector as air gets into the water. This is true with air injector, downdraft, and venturi skimmers. This causes more friction in the water path. Unless you have a strong enough pump to keep the water moving with this inceased friction, the foam "disappears" at exactly the time it's needed the most; when organic content in the water is at it's highest. Now, maybe the aquaC with a good pressure pump, like an iwaki, would work fine. I know my skimmer's performance improved drastically when I switched from a non-pressure pump (quiet one) to a pressure pump. (velocity T3) At some point I'll try an iwaki on it.

Within a week or so I'll have pictures of a new large dual beckett skimmer driven by an iwaki 70rlt. I'm pretty anxious to see how that one works.