I'm looking to mount a 6 bulb t5 retrofit to some sort of light fixture that would then slide back and forth on a sort of channel. So it woulnt be either really since it doesn't hang or sit on top of tank. I'm just looking for ideas on how others might have done theirs.Are you talking about a hanging fixture or fixture with legs that slides back?
I have one made out of channeled extruded alm. How long if a spread do you need? I have some left over. Can post picture later.