Hello, I've recently got round to sorting out the tank I refer to as the 11" cube out (its not really a cube its actually l11xd10xt12). I'm running 18watts of pc light over it currently but I can't help but feel worried that this isn't enough light for the plants I've chosen. I've ordered a second 18 clip on lamp but would this give me too much? 36watts is alot... It would give me nearly 2w per l If my maths is right... Anyone want to help me out?