radium bulb

[thepollock]

i just picked up the 400w 20k and i was wandering if any one here uses them. if they noticed better groth or no diffrence? i like the look of them thats why i got them. is there really a diffrence on teh bulb you pick? also i was wondering how people here burn there bulbs in.

[RaysReef]

not sure...but I think the burn in time is somewhere between 50-100 hrs.
20ks...the better the bulb the bluer the spectrum...and u got a great bulb. Bet it cost a pretty penny...As for growth 20k is the least kelvin effective for growth, don't get me wrong, you'll still get growth but not as much as a 10k (More of a natural light)

[David Grigor]

With proper water parameters, growth won't be an issue and your corals will look much more attractive which is more important to me than extra growth from a 10k xm.

It's a great bulb when running on a HQI ballast. I ran 2000w of them for 4 years. You get about 6-8 months use on them. It will burn in whiter ( about 2 weeks ) than on a standard ballasts. XM 20K is also a good alternative if there is a big difference in cost. I have bought any for years so don't know what they go for. I used to get them for $72. The 20K XM little burn a little more blue than the radium.

[mattb]

Part of the problem is that Radiums are HQI bulbs (even though most equate DE with HQI). If you don't run them on HQI ballasts they will be bluer and duller. The second problem is that there isn't a true 400w HQI ballast in the USA. The 400w HQI ballasts, like PFO, are nothing more than High Pressur Sodium ballasts. The 250 will act differently than the 400...

As far as MH goes, on HQI, they can not be beat, may be the reeflux, but they are real nice looking and the corals respond well. This is the bulb Tyree uses....