OK, so I'm almost finished with my nano tank that I built, already drilled, plumbed etc... the last thing I have to do is put the overflow box on... my question is... I've seen both types of overflow boxes, with the comb/teeth and then without them... my question is... cutting the teeth is proving to be a real b!tch... do I really need the teeth? or can i just have the box and let the water just flow over the top of it?