55 Gs are easy to light if you don't keep demanding plants. All you need is a single 48 inch bulb, 32 watt, 6500 K
, T8 or a 40 watt 6500 K
, T12 and you're "good to go".
Two Marineland glass covers work very well to support the light strip, that's what I use in my 55 Gs. There's plenty of light for low light plants. I have several 55 Gs I use to experiment with plants, substrates, liquid ferts and such. The bulbs work great and are easy to get at the local hardware stores for less than $10.00 each. Attached are a couple of pics of the tanks.