Radium vs. 20K XM

[WLachnit]

I am looking for opinions on the 250w Radium vs 20K XM lamps. From Sanjay's site, it appears that the Radium is a lot more efficient. What is the difference in color appearance in real situations.

[grigsy]

Both Radium and XM 20K are good bulbs IMO. Depends a bit on the ballast you have now. If you have an M58 ballast, you wont be able to run the Radium bulb. If you have an HQI ballast M80 or electronic ballast, you can run either the Radium or XM. If you do have an HQI ballast, I would definitely recommend Radium 20K. A very nice lamp driven off M80 ballast IMO.

[rigleautomotive]

i have ran both on electronic ballasts and i would say the radium has it beat in a few ways.way brighter with a higher par for sure.tested with a par meter and on the same ballast about 20 percent higher.better color on most if not all corals IMO.and lastly they hold there color longer and have a longer useful life.the only thing i feel XM has over radium is that it will fire on magnetic ballast(non HQI) and price.

[James77]

I've not seen the XM, but I read alot of + feedback on them. The radiums on HQI are a bright crisp white with a strong blue in it. Almost not blue enough for me- Id say it is more of a 14-15k on HQI ballasts.

[Toddrtrex]

I ran the XMs for about 9 months, and now running the Radiums -- both on a Galaxy ballast.

Too early to tell on the growth and color of the corals, but I think I like the color of the Radiums better, but not sure if I like the color enough to make up in the price difference.

One of these days I am going to take pictures of the tank with both bulbs (( since the Radiums are now fully burned in )). Plan on using the same camera settings for both pictures.

[WLachnit]

Thanks for the replies. I am running Icecap ballasts. So, it appears that the Radiums aren't as blue? I had tried Hamilton 14K and was surprised at how white they were which is why I was going to try 20K. Anyone else?

[James77]

The Radiums will be quite blue on electronic ballasts, as they are being underdriven. HQI ballasts run them to spec, so they are a bit whiter and have more output than they would have on e-ballasts.

[WLachnit]

Thx, do they last longer if they are underdriven?

[bluetang_2000]

the coralvue dimmable ballast has a 10% overdrive, will it be better for running the radium?

[burned]

I vote Radium, deep blue color!

b

[JAustin]

you can also get a M135 pulse start ballast and fire both. It will overdrive the XM a little and make it perform better than the Radium. I love both bulbs but am running an XM now. My next bulb will be a Radium.