I have a 160g tank which is 21,6" tall. I´m planing on filling it with anubias and moss. I´m hanging a light fixture over it with 4 39W T5´s. Now I don´t whant the light to be to bright since I dont whant the anubias to be covered in algae. I wont be using reflectors on the lights, how high should I hang them in order to minimize algea growth? Should I maybe only be using 2 39W T5´s? I thought that would be a bit low for a tank that size.