They offer a better spread for the light. Less shadows inside the tank. Better fill for light. That is afterall what they were made for. You shouldnt have too much difficulty with it unless your lights are far from the surface of the tank.serafino;2800180; said:That poses a problem with reef tanks though. You may have to increase you wattage to compensate for the diffusion. I personally have never had a saltwater fish jump out of its tank. I've had snails crawl out but they figure out how to get back in lol or I just plop em back.