Metal halide: How far above the water?

about a 12 inch tank with the frags on the bottom

 

You may want to get a higher canopy and build a sliding shelf for your light fixture so you can move it back and out of your way when your working on your tank. 8" above the water is fine so just screw in 1"x1"s or 1"x2"s on each side of the canopy after careful measuring and leveling and then get a 1"'x whatever the width you need. Example: if your fixture is 5" wide then a 1"x6" would be fine. Cut the length about 1/8" less than the inside width of your canopy so it can slide and not fall off. One thing though, get the best hardwood you can find for all the wood pieces. This will keep the shelf sturdy without warping. I used solid red oak for mine. The pics below show my setup. I have a 15" canopy and my T5 fixtures are 12" wide so I used two 1"X4" pieces and left a gap in the middle for air flow for the ballasts. This is just an idea I picked up on the web a long time ago. It also makes changing bulbs easier.

 

I put mine up high enough in my canopy that I can reach inside the tank without burning my arm on the Lumenmax reflector! I'm guessing about 6-8" up 250w halides on a 90g.

 

Thanks everyone.

I drew it up & don't like how tall the canopy is compared to the height of the tank..it dwarfs the tank.

 

I have my lights at 8" to the bulbs, my tanks 20" deep with a 4" DSB.