how high should i hang my lights?
 

I have an ATI 6 bulb T5HO fixture, Id like to know how high to hang it over a 18" deep tank.

(I do have C02)

I will be running 4 bulbs most of the time with the other 2 bulbs on for a peak period.

I'd say 10"-20". They would work fine much higher up but then everytime you look at the tank you get blasted by the light which is really distracting. Depends on the layout of the tank and the plants your trying to grow too.

I'm going for higher light plants.. Id like lots of reds. I'm going to try some L. Glandulosa, Ammannia Gracilis as well as some bushy greens and a nice thick bright green foreground.. not sure which yet, still in the planning stages. There will probably be a mossy rock in there somewhere too..