Hope i'm not over stepping my mark here, but from the specs of those lights it sounds like you're planning on using two of the aquatraders 18" fixtures??? Just be careful if you are planning that, as someone above stated the 14w actinics have a number of problems, first short t5 bulbs don't "penetrate" not such abad thing with actinics, but will be annoying if they barely illuminate better than moonlights, second the Odyssea brand actinics are pure CRAP, barely worth installing at all plus, you're only going to be able to buy those replacement bulbs from aquatraders in the future, no one else makes them any more.
don't get me wrong, i like odyssea fixtures, as long as you understand they're going to need a bulb swap straight out of the box, however, having said that, the 18" fixtures are a complete rip, look at the 24" fixtures, i think they're only 10/20 bucks more, but you'll be able to replace the t5's with ati or geissman bulbs, which you definitely will NOT be able to with the 18" fixture!