I have a very nice DIY LED over the seahorse tank (what I consider my main tank) but for the clownfish tank I just want something I can slap on top, grow macro algae with and look at the fish. Don't want to build anything.

I think Alton has the marineland fixture on his little tank. I'll see what he said about it. I think he had some kind of trouble with it (forgot what it was) but overall it worked well enough for him