I started with an Aqua-C EV120 on my 120g but I tee'd it off the main pump thereby pressuring the spray injector above the recommended 500gph on the skimmer and it did pretty good for an avg skimmer. I then switched to a Deltec AP600 and it did well for a small skimmer (5" body). I now run a Deltec AP702 on the tank cause I have since added another 100g of connected water & livestock plus I way overstock on fish in my system.
Fas the Tunze skimmers suck don't waste your money.
Dean, their small weak bodies draw very little air, with very little contact time, producing very little waste. For some reason if you touch that skimmer the foam collapses. Definitely not worth the cash.
For the money I would go with the ASM G4x or the DAS EX-2
You are welcome to come over if you would like to see my Tunze in action.
IMO, it is fine if you are really just on the verge of being skimmerless (i got it after running skimmerless) or just really have no room for a larger skimmer (it is better than nothing) as it is quite small.
For it's size, i would say it does a good job and it is silent and simple to use (plug and play).
Currently I am selling mine (as a 9010 or 9015 - i have both cups) to upgrade to a more powerful skimmer for my tank.
If you can fit something larger i would go with something stronger (even though i am looking to sell mine).