I am about to set up a new 125 gallon freshwater (this weekend - it finally came in!), which after initial set up and some bill paying off, plan to create a community and planted tank. The research I have done revealed 3-5 watts per gallon. My plan on the 125 is for 384 watts, 3 watts per gallon. For your 55, you would be looking at 165 watts at 3 watts per gallon. Take a look at the 48-inch compact fluorescent lights. They have 130 and 260 watt versions available. I'll also be utilizing one with lunar lights.
When I make the light purchase, I'll also be purchasing the CO2 injection and run the CO2 through a diffuser into the tank. I have heard about the best regulator on the market is the Milwaukee brand. Once, I make the purchase for the light and CO2 system, I will be looking at purchasing plants.
I have no clue on connecting the CO2 to the Fluval. I'll be running two Filstar XP3 filters, but plan on just using the diffuser system.
Good luck!
