I agree, I quoted 4 T8 bulbs since that is about 180w NOT12 equiv. a 100Gal with 2 T8 bulbs will not be that bright and growing all but the absolutely lowest light plants (Crypt, anubias and algae) will be difficult. However the bulbs I listed are for effectiveness and brightness. even going with 1 of each would be good. both are available from home depot for less then 5$ each. but I would highly recommend increasing the number of lights. if you intend to go up to high light w/ Co2 then Compact fluorescent fixture would be a nice addition.