400 watt Radium 20k questions???

[tmc1313]

I've switched from my Hamilton 400 watt 14k pendants to the Hamilton Cebu Sun fixture. I'm running two Radium 20k's with the recommended 400watt hqi magnetic ballast. I know the bulbs are new with only ~75-80 hours burn in time, but they seem to blue to me. So,

Will they lose some blue after burning in?

I was thinking of switching to an E-ballast, but was told by Hamilton it will actually make them look more blue (anyone experience this?)

Thanks

[alton]

How old are your magnetic ballast? As magnetic ballast get older they put out more heat and less power. I run 250 watters on electronic ballast and two of the three are doing very well around 13 months after checking with my meter. One has dropped off more than 20% so I am changing it out today. Even with that there is no difference with color or my eyes telling me the third one is bad. Check and see if you can borrow another ballast?

[Nanook]

They will whiten up a bit after a couple weeks. The HQI ballast will overdrive the 400 watt Radiums a bit and most folks only run them for 6-8 months due to spectral shifting. The ballast that most closely runs the bulb to spec is the pulse start ballast M135, but you will see less PAR with that ballast. The plus side is you will get closer to a year of service from the bulb, but a bluer look that you might not like.

[tmc1313]

They will whiten up a bit after a couple weeks. The HQI ballast will overdrive the 400 watt Radiums a bit and most folks only run them for 6-8 months due to spectral shifting. The ballast that most closely runs the bulb to spec is the pulse start ballast M135, but you will see less PAR with that ballast. The plus side is you will get closer to a year of service from the bulb, but a bluer look that you might not like.

So I will wait a couple of weeks and see if it lightens up a bit. If not, what ballast will run the radiums not as blue? Or, I might have to switch back to my Hamilton 14k's.

[Nanook]

HQI gives the Radium the "whitest" appearance, kind of an ice-blue-white for lack of a better description. They are sweet bulbs on HQI ballast, but the life is only 6 months or so.

[tmc1313]

HQI gives the Radium the "whitest" appearance, kind of an ice-blue-white for lack of a better description. They are sweet bulbs on HQI ballast, but the life is only 6 months or so.

That's what I have them on (HQI M135 hamilton magnetic ballast). Maybe they just have to burn in more.

[Nanook]

The HQI is kind of a misnomer. If you are running the M135 ballast by Hamilton, then you are running the Radium 400 watt bulb almost to spec...they will have a slightly bluer look with that ballast. The HQI ballast is a different animal which is actually a son agro 430 HPS ballast. This overdrives the Radium bulb giving the whiter look and shorter lifespan.

[tmc1313]

Ok, I'll look into the agro 430 ballast then. Good information, thanks.

[Nanook]

PaulErik was the lighting guru here for many years. This is an interesting read:

http://www.reefcentral.com/forums/showthread.php?s=&postid=14900490