well today I got a new bulb for my tank. The one I had came with my all-glass aqarium hood and wasn't all that bright it was only 15w so I decided I would go out and get a brighter bulb. The guy said the only ones he had that were 18" were Lightning Rod 11,000K 15 watt Ultra Daylight bulb. It looks alittle brighter but just a diffrent color. Are these any brighter or just the same? 
