Looking @ T5 lighting

Depends on what you're keeping and who you ask. /site/DesktopModules/NTForums/themes/_default/emoticons/smile.gif I think a 6-bulb fixture would be enough for a 75-90 gallon tank. The 8-bulb fixture would be better suited for a 120 since it's wider.

 

I have TEK 6 x 54 on my 90 and it is plenty of light to keep whatever I'd like.  I believe that all fixtures are not created equal however and the indiviual reflectors intensify the light put out from each bulb.
My TEK light has two switches, one that controls  the first and six bulb, and one that controls the four bulbs in between.  That way I can put actinic bulbs in #1 and 6 position and a combination of daylight bulbs in the middle and run the actinics for a couple of hours first each day (these are on timers) turn on the middle for the daytime and then go back to actinics for the last hour of the day.  I don't think I'd want them all on, all the time.