hi, i currently have HO fluorescents: 15" reef sun, 18" 50/50 and a 18" actinic in my 25 gallon tank with corals and fish. i dont know whether the lights are quite bright enough, the corals seem to be ok- although sometimes they don't come out, what do you think? is the lighting up to scratch?
i dont think you can really get by with just those bulbs you can buy at petco. i use 2 of those over a 20 planted and they just barely allow my plants to grow. maybe if you keep only low light corals at the very surface...but that would be awkward.