Item Code: 23-HRI-T400W-BLU
* Radium 20,000K - Crisp Blue Hue
* HRI -T400W/BLUE/357
* Mogul Base Metal Halide Bulb
* Made in Germany
* Approx. length from end-to-end: 10 1/2"
FAQ:
Q. What ballast do you suggest for the 400W Radium 20,000K bulb?
A. The 400W Radium lamp is a European lamp for European ballast applications. The lamp was designed for a reactor ballast used for 220/240V input voltage and not for 120V operation in the U.S. We recommend the use of a 400W pulse start ballast (ANSI M135) for these Radium 20,000Ks because M135s provide a higher starting voltage and use an igniter to assure lamp starting. It is our experience that M59 ballasts can have problems with these bulbs flickering, not starting and/or being unable to keep the lamp fired (ie. it will go out after a while).
General FAQ:
Q. What are the ANSI codes for Probe Start and Pulse Start ballasts?
A. Probe Start ANSI Codes for Metal Halide lamps: M102=150W, M57=175W, M58=250W, M59=400W, M47=1,000W.
Pulse Start ANSI Codes for Metal Halide lamps: M85=70W HQI, M81=150W HQI, M137=175W, M138=250W, M135=400W.
Q. What is the deal with "pulse start" or "probe start" ballasts?
A. "Probe start" ballasts are more common in the U.S., while "pulse start" ballasts are more common overseas. Most aquarium lighting hoods and pendants sold here in the US have PROBE start ballasts, as most MH lamps sold here are made for those ballasts. However, the short list of PULSE start style lamps commonly sold in the aquarium trade would be: 175W and 400W Ushio 10,000K, and both 250W and 400W Radium 20,000Ks. Those lamps will generally operate fine on pulse start ballasts, and we see little to no problems. We sell both pulse and probe start ballasts so you can get the correct one for your lighting needs.