20k Radiums

[BigLar]

How long do the 20k Radiums last?

I currently have 3 - 400w Iwasaki's running without supplementation. I'm contemplating adding 2 - 250w 20k Radiums or maybe just replacing current setup with 3 - 400w 20k Radiums. What do you think?

If I decide to replace my ballast with PFO HQI ballasts to run the Radium bulbs, will the quick disconnect cord and mogul socket still work? My Spiderlights are still good with this setup right?

[golfish]

BL,
The quick disconnect and sockets should all be the same. I take it you have MV (EYE) ballasts? NO room for VHO's ?

From what I have read the Radiums are good for 6 months then they start to go bad. Their kind of expensive too. If you don't mind the cost then by all means go for it. Their a nice looking bulb.

Mark

[golfish]

I like what Dr Mac had to say. If anybody would know, he would. I wonder if this hold true running them with the PFO HQI ballast?

Mark

[Ninong]

Well, Dr. Mac certainly does get spectacular SPS coloration using Radium 400w 20,000K HQI lamps on Blueline ballasts and, in his opinion, the Blueline ballasts appear to burn the lamps 25% brighter and whiter than PFO ballasts.

However, Sanjay tested those exact lamps on those exact two ballasts early last year and the results were: 114 PPFD on the Blueline and 110 PPFD on the PFO HQI... a difference of only 4%.

What Sanjay did say (and this is what Mark is talking about) is that the 400w 20,000K lamps started to shift a lot at around 6 months and lost intensity pretty fast compared to other lamps tested. Sanjay recommended changing them at 8-9 months. Dr. Mac has come up with a way to make them last 12 months: he just keeps lowering his fixtures as the lamps age and then replaces them at 12 months, or less.

Ninong

P.S. -- I would love to see some tests done on the little 150w 20,000K DE lamps. I wonder if they might not be just as strong as the 250w 20,000K HQI mogul base lamps? The 400w size are just too pricey and run too hot for me. It seems that double ended lamps are more efficient than comparable wattage single end lamps. Probably has something to do with burning the candle from both ends.