Position of MH bulb when screwed in socket

[olemos]

Some time back I read a thread that advised setting 400w MH bulbs in a certain position but I cant remember.
This was not related with direction of tank, it was related with when you screw the bulb in the socket there is a piece in the bulb that either should be position vertical or horizontal to the water surface.
Will appreciate any info on this.
Tanks

 

[Blown 346]

I actually just screwed mine in until they were tight, I havent had any problems.

 

[tunaluver]

i just read something yesterday about the nipple bein in a certain position.. thats actually wat im lookin for right now

 

[dwdenny]

Yeah there is a nipple on the inner part and should be in the 11-2 o'clock position pointing at the reflector if I remember correctly HTH

 

[tunaluver]

http://www.reefcentral.com/forums/showthread.php?s=&threadid=806698
found wat i was lookin for.. 11 or 2 i guess is about the same thing

 

[olemos]

Thanks tunaluver, this is it

<a href=showthread.php?s=&postid=7012639#post7012639 target=_blank>Originally posted</a> by jdieck
Zimmy:

Just in case. Check the following. Many metal halides turn green yellowish if the nipple (pointy glass) in the internal bulb is pointing down, if it is so try screwing the bubl so the nipple pints either to the sides or up. if the bulb does not tighten properly you can use your index finger to try to pull up the center contact in the bulb socket (the metal flat tongue in the center bottom of the socket)