I have an aqueon 15 gal tall tank. The stock light is an 8w t5. Is this good enough for low light plants like java fern, annubias, swords, or should I add more lighting? I have seen people using the compact cfls to supplement. Does it have to shine down from the top or would shine through the side glass work(like a swing arm desk lamp pointed through the glass)? I don't want to have to modify the hood. If this would work, what kind of bulb is best.