The main thing to look at is wattage, and 'colour' or spectrum, which you don't mention. You have a pretty normal NO (normal output) fluorescent, and if you don't mention a special spectrum I'd assume it's somewhere between 4000 and 6500K.
By saltwater standards this isn't terribly bright, but there are plenty of things that will grow in this strengh, contrary to what people tell you, however I would very carefully research any corals you may want - it's got nowhere near the 'punch' you need for many of these. I would also suggest swapping out at least one of the tubes for one that is definitely 6500K or 10000K, which is a bit more 'bluey' white. The lights you have at the moment are better for freshwater plants but you may find they are good for algae growth.