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View Full Version : Odd lighting discovery, Any thoughts?


Jason McK
12-28-2007, 04:27 PM
I run 3X 400W MH 10K XM. on Blueline e-Ballasts. All bulbs were changed at the same time roughly 4 months ago
through troubleshooting an unrelated issue I swapped the middle bulb with the left hand side bulb.
the bulb now on the left hand side was 1000X bluer than the other 2 bulbs. So the next step was to switch the ballast. So I swapped the middle ballast with the far left. So the far left bulb and ballast where back to the original configuration as before I started but they are still way bluer.

Now before I started switching positions I didn't notice any colour temp difference between bulbs.

Any thoughts?

J

untamed
12-28-2007, 04:38 PM
I've often wondered if the ballast/bulbs behave differently if they are the 1st or 2nd item to draw power from a particular circuit.

I'm not sure that this comment helps you in any way, but your question made me think about it again.

Jason McK
12-28-2007, 04:46 PM
That could have been the case. When I switched ballast I did not change the input of the ballast only the output. So the plugs to the power bar are the same. + the light was not different prior to my switch.

Thanks though.

J

StirCrazy
12-28-2007, 04:48 PM
could me a bunch of different things, wiring, quality of the connections, reflectors, bulbs aging, balast differences, even down to the design of the tank and what is under the bulb causing different reflections.

Steve

fmelindy
12-28-2007, 04:50 PM
i used to run 3X 250 watt 10k xms in a similar configuration on ice cap ballasts and noticed the exact same thing. I thought I was going crazy! good to hear someone else noticed the same thing. I switched out every ballast and every bulb and continued to notice the same thing - the order that the ballasts were plugged into the power bar definitely changed the perceived color of the bulbs. strange phenomenon and I thought it was just my setup...

Jason McK
12-28-2007, 05:13 PM
I did wire the reflectors myself. Still crazy that that the light was the same across all 3 bulbs before I started to change things.

It is definitely different light output. I am able to swing the lights out from above the tank and used a light meter on all three bulbs using a grey card. The difference is significant

J

Delphinus
12-28-2007, 05:38 PM
Maybe the fact that the bulb got shook up, moved around a little when taking it out and back, somehow affected the arc tube? Maybe we need to make it a point of routine to shake our lamps a little every couple of months? :lol: Wait, is it better now that it's different, or worse?

Or ... hmmm, wait, yeah you said you're using electronic ballasts. I wonder if a lamp just gets "used" to a particular ballast, and after switching them, they have to sort of re-burn in? Maybe it's just enough of a difference that even switching back to the original ballast is still different enough now that it still needs to go through the re-burn-in phase?

(Just grasping at straws here really ... it's rather quite a bizarre observation!)

Static
12-28-2007, 08:51 PM
just a suggestion, but maybe you've turned the bulb upside down, so the part facing the top is now on the bottom and that made a difference somehow?