400W 20K Radium question

[droptheleash]

For those of you who are running 400 watt 20K Radium halides...

How old are your bulbs when you start to notice that your SPS corals begin to lose some color/vibrancy, as a result of a decrease in intensity or spectral shift?

In my case, I begin to notice a color change after 2-3 months, which is alarmingly fast considering the cost of these bulbs. My SPS continue to grow well, but the blues, purples and reds lose their intensity.

I've been replacing the bulbs every 9 months, which is about as often as I can justify from a cost vs. coloration perspective.

FWIW, I use PFO HQI ballasts and have the bulbs mounted in Lumenmax reflectors. The halides are on for 7 hours/day. I also run VHO actinics.

I am curious if there is something unique to my system that is causing the bulbs to wear out prematurely, like too much heat or
a faulty ballast.

 

[reef.fishman]

The 430W S145 ballast overdrives the lamps and shortens their life. The recommended ballast for that lamp is the M155/M135.

 

[droptheleash]

Thanks for the reply fishman, I am aware of the fact that the PFO ballast overdrives this bulb and shortens its life.

I am mainly interested in learning what others have experienced, in terms of bulb life vs. color change in their SPS. I know there are a lot of people who run these bulbs.

 

[reef.fishman]

Oh. I get it.

I am running them on an M155 and I re-lamp every 3,000 hours. My lamps are staggered in age, so that no two lamps have to be replaced at the same time.

I don't see the color fade that you're describing.

 

[droptheleash]

I'm at a ridiculously low 500 hours before I notice the corals start to change colors. Yikes!

 

[just dave]

That's always been the " fly in the ointment" when using the "400W" radium on the 430 w SON AGRO ballast , you're over driving them severely and the useful life is dramatically shortened.
Another thing to remember is that it is really a 360w lamp not a 400w unit and was designed for the M135 ballast.

 

[droptheleash]

Have you run this bulb/ballast combo dave? If so, did you notice that your corals began to change color in such a short amount of time?

 

[reef.fishman]

<a href=showthread.php?s=&postid=14555075#post14555075 target=_blank>Originally posted</a> by just dave
That's always been the " fly in the ointment" when using the "400W" radium on the 430 w SON AGRO ballast , you're over driving them severely and the useful life is dramatically shortened.
Another thing to remember is that it is really a 360w lamp not a 400w unit and was designed for the M135 ballast.

I think that most people who lack an engineering background tend to underestimate the damage that they're doing to the bulb when they overdrive it, because they don't really understand what is happening. There are technical charts that show the change in lifespan when the bulb is driven above/below its rated specs. They're known as de-rating curves. Although you don't commonly find them made available to consumers, the engineers that make the lamps have them. Overdriving a device beyond its rated specs results in rapid failure. Always.

The son agro ballast uses FAR more current than an M155. The difference in peak current for the Advance CWA circuits is 5.2 amps vs. 3.8 amps. You're driving the lamp at 137% of its rated current. I'm surprised that the color lasts 500 hours under such abuse.

There's a proverb that says that the brightest light always burns out the quickest.

 

[just dave]

<a href=showthread.php?s=&postid=14555185#post14555185 target=_blank>Originally posted</a> by droptheleash
Have you run this bulb/ballast combo dave? If so, did you notice that your corals began to change color in such a short amount of time?

I have not because I've had no desire to use such an expensive bulb on a ballast that will shorten it's life so dramatically. Many people that use that combination were reporting about a 3-month bulb change interval.

I have used them on Blue-line E-ballasts and they seem to drive them at about 380w. I did think they had a crisper look to them compared to the XM 20k 400w bulbs on M59 ballasts but ultimately the differences were not worth the difference in price.