The only 18" T5's I know of are made by current. I am not impressed by their lamps and I am not even sure if you can get the ballsts. In all honesty I would grab one of the 150 watt halide clamp ons fixtures with a 20K lamp for that tank. That will keep your clam and anemone happy and look cool.
thank you for the reply grim, i did a little research and as you said theres really no choice out there. i just didnt want to go to the metal halide route as i dont want to heat up my tank too much and of course the cost of high electric bills.
im almost tempted to go with a 24x12x14 tank so i can get the 4 lamp combinations as you've discussed here a lot.
abr6