Are u planning to use high light demanding plants...6 lamp t5 ho is a lot for a 75 gallon tank.
I currently use 6 lamp set up by Tek Light for my 120 gallon tank. Works for me.
The fixture you are palnning to use, does it allow you to turn on some of the lights for dawn & dusk affect? 2 Backlit ON/OFF switches power cords for better lighting control. One switch controls the outer tubes while the second switch controls the inner tubes. The 2 outer lamps I leave on for 12 hrs and I run the remaining lamps on for 7 hrs.
http://www.specialty-lights.com/teklightaqua.html
Later!
