MH Bulb Position

[dobbs]

I was just cleaning the glass lenses on my light fixture. I noticed that the "knock off tip" on both MH bulbs are in the down position - facing the water. I thought I had read somewhere that they should be pointing up. Any idea? If so - how do I remove the bulbs wiyhout toucking the bulb? It doesnt look like there is any other way???

Dave

[csb123]

Use some latex gloves if you don't want to prints on the bulbs. I heard that the "blip" just needs to be above the horizontal plane.

[David Grigor]

Yes, you hear lots of reports that the dimple should be facing upword anywhere between 9 and 3 o-clock. However, there is no absolute. If your having trouble with the bulb not firing may be worth doing. There are screws that hold the mogul to the bracket you can unscrew the mogul and give a quarter or half turn ( dpending on how many screws hold it in may only be 2 ) and put it back. However, there is no hard data that says this makes any difference with light output as some will claim.

Also, it is good to use socket lubricant ( can usually be found at Menards at the checkout counters for like a $1 comes in bright orange disc. ) that will help not only make better contact but also easier to screw the bulb all the way.

[dobbs]

Originally Posted by David Grigor

Yes, you hear lots of reports that the dimple should be facing upword anywhere between 9 and 3 o-clock. However, there is no absolute. If your having trouble with the bulb not firing may be worth doing. There are screws that hold the mogul to the bracket you can unscrew the mogul and give a quarter or half turn ( dpending on how many screws hold it in may only be 2 ) and put it back. However, there is no hard data that says this makes any difference with light output as some will claim.

Also, it is good to use socket lubricant ( can usually be found at Menards at the checkout counters for like a $1 comes in bright orange disc. ) that will help not only make better contact but also easier to screw the bulb all the way.

Thanks David.

No problem with firing. I think I'll just leave them til I change bulbs.

Dave

[pogodzib]

Most people say to use either the 3/9 position or the 12 position based upon the bulb brand. I have noticed a color difference with two 250w XM bulbs based on nipple position, but not with any other brands. There have been a couple of article written about differences in light intensity based upon orientation, but nothing that I am aware that proves that one way is aways better than the other.

Here are the articles:
http://www.reefkeeping.com/issues/2006-10/bp/index.php
http://www.advancedaquarist.com/2002...ew?searchterm=