You should have no problem at all....
I have Ray IIs on 3 of my tanks and a Fugeray on a 2.5 gallon.
The Finnex output is strong, you will not be disappointed. On that note though, I wished they make the Ray II in smaller sizes so that I didn't have to get the Fugeray. The output is not as strong and it also has the blue moonlights for use at night...who actually uses it? Lol
I asked them about it, they're not making it anytime soon. They felt a tank so small wouldn't require such high output in the sizes of 10 and 12 inches...I can see the reasoning behind that, but oh boy, I was spoiled with the Ray IIs initially.