Thanks I was just wondering I would like to have some clams but was not sure wether that would be enough light. Every one says they require a lot of light. The tank I'm going to use the light on is a 30 or 40 gal. Not sure It was given to me. but it is 36" long. I have xenia, annemone, toadstool leather, flower pots,. The light I have now is just not strong enough.