i think those light are good .they say t5 are the best compacts out right now .+ the bulbs are cheaper {i think}.....you could grow most leathers, all shrooms, lps. and mabie some montipora digita..
that will be perfect, i have t5's on my 40 gallon 3 x 39 watt daylight and 3 x 39 watt actinic + lunars (234 watts) and its werks great i keep both lps and sps, but make sure you place most lps twords the bottom of your tank.
are you guys sure its right for his tank. most lights specs are based off of taller tanks.its only a 20 long tank, its shorter than most. maybe he should hang the light from the ceiling?