View Full Version : MH bulb height?

Deweys Dad
06/26/2006, 07:14 PM
My 90gal came with a canopy that is too low to install my MHs so I'm going to be building a new one. What should be the installed height of the bulbs above the water? If it matters, they will be dual 175s or 250s and the tank is 24" deep.

06/26/2006, 07:57 PM
mine are at 12", some may find it a little high but I don't have to clean the bulbs or the reflectors. Most people have around 8 inches.

I have 2X175 over a 90G

06/26/2006, 08:00 PM
Sorry to Hijack.... but what would you all say would be the absolute minimum height for 150W halides?

06/26/2006, 08:09 PM
I don't think there is an absolute minimum, but if you put them at 3 inches you might have to clean them very often. 150 DE have protective shield, but I've heard of SE bulb that exploded because of splashing water.

06/26/2006, 08:17 PM
I have 250 and 175 XMS @8 inches. No problems at all

06/26/2006, 09:22 PM
I'd go with 250w for your tank, btw.

I run my MH at 9".

06/27/2006, 05:21 AM
I run my dual 175 watters over my 55 gallon about 7 inches from the surface. No heat problems or any other problems at all.

06/27/2006, 09:40 AM
I run dual 250's over my 75 at about 8" off the water

06/27/2006, 09:42 AM
400w at 14 in