IIRC the new style PFOs are specular reflectors like the Lumenarcs (smooth surface). The old PFOs are diffuse reflectors (dimpled surface).
If you have a new style PFO and a small tank, I wouldn't expect to see a huge gain going to the Lumenarc. If you have the old style, then going to a new style PFO or a Lumenarc would be a big improvement as mentioned.
The lumenarc will give much better coverage over a large tank, but with a tank your size, personally I don't think there'd be much benefit to spending the extra money.
JMO of course. :wink: