250 Watt 20000K Metal Halide Bulb - German Radium, Mogul Base
$87.49
Item #: MB6811
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The German-made Radium 20000K metal halide bulb offers excellent coloration and good intensity. It is crisp-white with a strong blue tint. It brings out the fluorescent pigments in corals nicely. Fluorescent supplementation is usually not necessary, but can be used for added intensity and to simulate dawn and dusk. An electronic ballast, magnetic pulse-start ballast or magnetic HQI ballast is required to ignite this bulb. This bulb is white with a blue tint on a magnetic HQI ballast. It will burn more blue on an electronic ballast or pulse-start ballast. An excellent choice for reef tanks 22"–30" deep.
Common questions/problems concerning metal halide lamps:
- Metal halide lamps of the same kind are different colors?
Metal halide lamps operate by passing an electric arc through an arc tube that excites particles in the arc tube. When the metal particles reach an excited state they emit energy in the form of visible light. It takes 100 hours of operation before the metal particles stabilize and become a consistent color. All metal halides require 100 hours of operation before color and light output stabilize. All metal halides inherently have a slight color variation between individual lamps. - The metal halide lamp fires and then either burns dull or the arc extinguishes?
Usually the ballast and lamp are not receiving enough power. Metal halides pull a high current. Usually the problem is either there is too great a load on the circuit or the extension cords are of a small wire size and can`t handle the power needed by the ballast. Use only heavy duty extension cords and try running a ballast off a circuit from another part of the house. - Do I need a cover shield between the lamp and the aquarium?
Metal halide lamps produce a large amount of UV and also have a potential of exploding. The single ended metal halide lamps have an outer jacket which eliminates most of the UV. However, they have an inherent risk of exploding and UL requires metal halide lamps to be enclosed. On double ended lamps there is no UV shield. Double ended lamps must have a glass shield or major eye injuries including blindness may occur. - Can I operate a ballast and lamp together which are designed for different wattages?
Each wattage lamp and ballast are designed together for optimal performance and safety. If you over drive the lamp it may explode and shorten the life of the ballast and lamps. If you under drive the lamp it will also shorten the life of both components and also may explode. Do not mix different type wattages of lamps and ballasts.
*Requires HQI ballast, electronic ballast or pulse start ballasts to work properly.
| Bulb Replacement Guide | |
| Bulb Types | Life of Bulb* |
| Normal Output Fluorescent | 6-12 months |
| Very High Output (VHO) | 6-12 months |
| Power Compact (PC) | 9-12 months |
| T5 High Output (T5HO) | 9-18 months |
| Metal Halide | 9-12 months |
| LED (non-moonlight) | ~5 years (50,000 hours) |
| * Manufacturer Recommendations | |
Manufacturer information
Radium
Radium was founded in 1904 in Wipperfürth, situated abt. 40 km north-east from Cologne in the `Bergische Land`. Already a short time later the production of lamps with high-quality tungsten wires started here. Due to its know-how Radium advanced fast to one of the most important companies of the region and nowadays counts among one of the most experienced brand-name manufacturers of the lamp industry.
5 Stars
jube66
Reviewed on
March 05, 2018
Yes, I would recommend this.
Radium 250watt bulb
Pros: Beautiful spectrum of light it produces, quality made bulb
Cons: A bit pricey
Absolutely the best looking halide bulb out there. Produces a great spectrum of light and growth was good when used for a few years over 120 gallon mixed reef.
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checkitout
Reviewed on
August 22, 2017
Yes, I would recommend this.
The only bulb worth buying
Pros: Great look and growth
I've been using these bulbs for years now and they work amazingly.
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brian alten
Reviewed on
July 01, 2016
Yes, I would recommend this.
As good as advertised
Running the 250w on an hi ballast, gives a nice crisp white/blue, very close to what I have with the Phoenix
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howard bladen
Reviewed on
May 29, 2014
Yes, I would recommend this.
Great bulb
Been using this bulb for the last 5 years on my 180 gallon with soft corals. Corals have been growing and I love the blue spectrum. I have 3 bulbs suspended about 18 inches above the tank.
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otis glamore
Reviewed on
May 07, 2014
Yes, I would recommend this.
ok bulb
This product is a fine one, if you can get one that isn't damaged. The first bulb was cracked or scratched, which means "DO NOT USE". The replacement unit was undamaged. What is especially nice is the color, which creates a very natural "blue" tint and really makes the colors of the corals and fish pop.
Was this review helpful? 3 0
tin dang
Reviewed on
April 21, 2014
Yes, I would recommend this.
400W Radium
Excellent!
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dennis erickson
Reviewed on
June 04, 2013
Yes, I would recommend this.
400 Watt Radium 20K
The 20000K bulbs are great, a lot more light then the 250 watt bulbs, but that also comes with more heat and the chiller has to work harder. The blue tint from the bulbs make the corals pop with more color.
Was this review helpful? 1 0
elton garcia
Reviewed on
April 07, 2013
Yes, I would recommend this.
radium 20k bulb
The bulb works great and gives off great shimmer. The corals seem to like it as there is great polyp extension.
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scott gregory
Reviewed on
March 04, 2013
Yes, I would recommend this.
Great Customer Service
Your service and follow up on my purchase was excellent. Have used these bulbs before and had downsized my tank but I am now back using these bulbs. I honestly forgot how nice they were. Thank you! I'll be back!
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eduardo hernandez
Reviewed on
December 27, 2012
No, I would not recommend this.
not a true 20K
Great price and good intensity but does not match up with my other bulbs.It has more of yellowish tone
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