thank you all for sharing your experience. this is for a 16G cube(16x16x16), it currently has 18W PC, was thinking of adding a couple more bulbs. with the 19Watters that would give me 56W. i think that should be adequate, it is primarily for a mantis tank, i just want to be able to keep some polyps in there to make it more interesting. i'll be building a custom hood so i can add a fan no problem. what kind of sockets are you guys using?