How tall to make it

[lilredwuck]

I have a 90 gallon tank I will be setting up. Going to make a canopy for it. I have 2 175w metal halides and 4' reflector. How far should the lights be from the water or the glass lids. Should I use the glass lids? How tall should or does the canopy need to be? I plan on the open back or at least partially open and plan on having fans in the canopy as well. Let me know so I can get the lumber and get to work thanks

 

[bulldog123]

The higher the lamp the wider spectrum (within reason). So with that thought I would have the bottom of the lamp 6" to 8" off the top of the water. I would also remove the glass-top it will allow more evap and help with gas exchange and cooling of the tank. HTH

 

[jetskiking]

I used a standard 1x12 for the height on my 120. with the backspacing to cover the lip of the tank and 5" tall fixtures it put them about 6" off the water.