I am still learning and no expert on this but based on your plant density relative to your lighting, you may end up with serious algae issues sooner or later, not to mention possible overheating issues.
I have the same tank that pretty much overheated with a 30 watt compact fluorescent. It had DIY c02 and fairly high plant density. You may have better luck. I finally tore the tank down, replaced the light bulb with a single 10 watt coralife colorax and converted it to a Diana Walstead Type Natural Tank, as described in the link below.
http://thegab.org/Articles/WalstadTank.html
This is a picture of the tank after conversion.
If you are going to go with what you have, I would seriously suggest increasing plant density, reducing photoperiod to no more than 7.5 hours, and dosing with fluorish excel in addition to the c02 to prevent algae from getting a stranglehold on your tank. IME, it is a lot easier to prevent algae than to deal with once you get it.