....I have done a few weeks of research, and I just wanted to make sure I'm on the right path for lighting my 54 gallon corner tank....I would like to eventually keep some clams, and I am planning on building a cave in the center of the tank.....I am thinking of using a 175 mh setup with some actinic backup, is this enough, too much, just right? Will it melt the plastic joint in the glass top? Should I go without the top? I know this type of question is asked often, but I am finding it a bit overwhelming to make a final decision, and my lfs is steering me towards pc lights.....also,,should I ditch the cannister that my lfs sold me? Thanks for the help, and sorry for asking such old school questions.......