Hey Everyone,

I an putting a Venture 5K 175W MH in my M-250A2 and it operates horizontally. I have heard some stories that universal metal halides will operate at different color temp. in different positions and is this true? Also doesn't the arc tube bulge after some time? Does anyone have a picture of a bulged arc tube?

Thanks,

Aaron

Yes the arctube will eventually bulge.  The color should be about the same until the arctube starts bulging and the arc starts getting farther away from the MH salts, in which case the lamp tends to shift to a higher color temp.

Yes there can definitely be color shift and arctube bulge as seen here and here.

This concerns universal burn lamps.

I have also tested various brands of 175w universal mogul base M.H. lamps in my M250's. From what I have seen, the GE's and Philips I've tried, they seem to run a bluer color when operated horizontal. The Sylvania's that I tried didn't seem to be as blue but that could only be an exception. I also have a 400w Sylvania MH in a Silverliner at work and after 9 months, it still makes a nice whitish light. I haven't checked the arc-tube yet, though.

Thanks Guys!!

Just remember, when it starts to color shift, replace it soon otherwise BANG! 

Just remember, when it starts to color shift, replace it soon otherwise BANG! 

That is very true... I have seen it myself - Not long ago I used to walk past a furniture store every day. The store has a freestanding sign lit with MH floodlights.
Anyway, I noticed that one of the lamps was going dimmer and a funny green colour, getting worse each day it seemed (the lights were on 24/7). Then one day the light was out... with a pile of shrapnel in the fixture!

The store I work at is lit with coated O rated MH lights.  Every now and then, one would go dim and pink.  It would work like that for a week or two, than it would be out.  Ya walk by and look up and could see what looked like fragments in the bottom of the bulb.  It maybe out for a week or two than get replaced.

The lights where on steady burn for the most part, 24/7, except at night they would get cycled off for 15 minutes a few times a night.