MH Nipple Orientation

[mojoreef]

Yea I have seen and done this many time on my reef. When all the talk was out about this I used to do it for folks to show them the difference. The difference if not just a slight thing it is a HUGE difference. For me it was with Ushios and radiums both 400 watters.


Mike

 

[Boomer]

Next time you guys run test and comapre bulbs look at the arch of the plasm arch tube and compare it to a std MH. It is usaully the arched tubes that cause the greatest difference in orientation.

What Kev says here is somewhat true.

Another thing that can happen after using the bulb for a while is that the halides/carbon that condense each time the bulb goes off can collect in the nipple tip and not totally vaporize upon ignition and if the tube has a high arch the "products" collect in the two pointing down oreinted parts of the tube and do not get full totally vaporize ignition, as such a location casues cooling

 

[Kensn]

Mike, with your experience, what is the best way to run them then?

 

[Woodstock]

SUn Aquatics SE 250 MH run better with the nipples up. I just tried both up and down. They are yellow when the nipples face down.

 

[NaH2O]

I can't argue with the anectodal evidence. I'm due to change out my bulbs and may try it out. Do you need a welder's mask to see the arch (yes I know not to look at the bulb, but didn't know exactly what you can use)? My confusion really comes into this....if Harker knows what he's talking about/doing, then why such a difference with the data, compared to what folks actually see? I would think the color difference would be much larger (up vs. down) with his results. I don't get it . Unless the small color difference noted in the second experiment IS large enough for our eyes to pick up.

 

[Scooterman]

Nikki a welders mask would give you an good look at it. So some MH lamps have no Nipples, the BL 10Ks I was using was just rounded, guess it had no Arch.

 

[mojoreef]

Ken I cant pretend to have a clue about what the cause is, its just something that happened and I have always kept them up since the event.

No biggie really

MIke

 

[Kensn]

Thats where mine are. (chooses not to make lude comment)

 

[sanjay]

If someone has a lamp that is showing such drastic color change due to nipple orientation, I will be happy to test it and verify the color and spectrum change. I personally have not come across large color changes in lamps due to orientation issues. Yes, there is difference in PPFD readings due to orientation issues, since I am only taking single point measurements and the nipple pointing down interferes with the light output since my recieving sensor is below the lamp. I always test with the nipple in the 3, 9 or 12 position.

sanjay.

 

[MikeS]

Not an MH expert by any means...just curious here....could it have something to do with the thickness of the glass possibly? I mean the nipple is a result of the manufacturing process of the bulb, ie where the motlten glass is pinched off...is it possible that the glass in the lee side of the nipple is thicker, creating a slight refraction issue?

Like I said, I'm no expert at all, just throwing out that idea....

MikeS

 

[Scooterman]

Mike that Nipple is purposely made, My BL MH doesn't have a nipple. I think it is for condensation or something of the sorts.

Edit:
The nipple size is purposely made, it isn't necessary to have such a pronounced nipple unless there is a design reason i.e.. condensation.

 

[Boomer]

The nipple is where it is cut off from the glass blower.


edit:
Never nind I see Mike already gave the answer