SueD, I also got the Fluval Spec V. I chose the Finnex FugeRay 16" which will puts ,e in the low-to- low medium light (about 30 PAR at 12" height but it sits just below 11").
The other option within the Finnex line is the Ray II 16" or 18". Though the 18" is perfect in terms of length, it will definitely put you in the lower ranges of high-light. The Ray II 16" is solidly medium light.
The main point here is to determine what kind of setup and flora you want. If you're aiming for low-tech, the Fugeray 16" will likely do very well. If you're aiming for high-light, high-tech, then the Ray II is the way to go.