Is it enough? That depends on how you define "enough." The 170 is rated at 170 gallons per hour and is supposed to be ok for use up to 30 gallon tanks. But honestly it really depends on what you are planning on stocking in the tank.
If you plan on stocking the tank heavily I'd get a stronger filter. If you plan on stocking the tank lightly then don't worry about it. If you are planning on stocking somewhere in between these levels then its a judgment call. I personnaly don't have faith in the penguin models specs so I'd opt for stronger filtration (an Emporer) if I was going to own the tank though.