My lighting is a 48" TEK with 6 bulbs that are 54 Watts apiece. The tank is a standard 75 gallon. I think it works out to be 324 Watts in all it is 4.32 watts per gallon. All the bulbs have individual reflectors.
id say you can keep any clam. you may want to keep something more light demanding like a maxima or crocea up higher in the rock work, but for the most part your lighting is fine.
You should be fine, I have a 55gl. and I run the Aquactinics TX5, 5X54 T5's and I have my crocea clam on the sand bed and his growth has been excellent. Hope this helps.
Mark
Hey guys thanks, so Maximas, and croceas are more light demanding then? The clam that starts with a "s" do they get big? I am sorry I cant think of the name Maybe squamosa or something like that.