Sun Aquatics 14K bulb very similar to radium???

[Aquattro]

I just had the chance to fire up 2 400w 20k bulbs on my Son Agro ballasts and I find, for the 30 minutes I ran them, that they are brighter and whiter than Radiums on the same ballast. I'll fire one in a M59 tomorrow. They are almost too bright, as the colors of the tank seem a bit washed out, but that could just be the visual difference of running 10k just before swapping.
Unfortunately I'm just testing them for someone and have to return them, so I can't say what they'll do after 100 hours. Or 6 months. Overall, if you like the radium look, these might fit your need, for 400w anyway.