I agree with going with the full module. It would do a nice job of lighting part of your tank, but you're not going to be able to light the whole thing unless you hang it very high, but then your PAR would reduce significantly. I believe the SOL fixtures are the best LED fixture out there and almost the same price as just building a fixture yourself. If you go with something besides LED, you're going to spend the additional pretty quickly in just bulbs and electricity. I would save up a little longer and get the full module. And like Binford said, then you have it for the future too.