Frag tank lighting height help

[jonnyvexilar]

Hi guys I recently set up a frag tank it's 30×20×10" my lighting is 4 39 watt t5s with 2 10000 K and 2 actinic bulbs with 9, cree royal blue leds with 80 degree lenses about 3" apart ran in a line in between the 2 t5 fixtures, it's a z and p grow out tank, what height would ever body suggest I hang the lights, I have them at about 30" off the surface and I'm not sure if I should be higher or lower? Oh and the leds aren't dimmable forgot to mention that.. any and all advice is appreciated thanks

 

[Reefing Madness]