New MH bulb question

[omreardon]

I was installing my new double ended radium bulb and noticed that the bulb has a little glass bump in the middle. Does this bump go up or down or does it matter?

Thanks!
Olivia

 

[macclellan]

There's been a lot of debate about that. It doesn't seem to matter much, as plenty of people argue both sides and use both sides. Personally, I'm a 'bump downer'.