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250 Watt 21000K Metal Halide Bulb - Megachrome Blue, Double Ended


MB6865

This item has been discontinued.

Giesemann Aquaristic

We offer a wide variety of Metal Halide bulb choices to suit your aquarium lighting needs.

Most of the MH bulbs in the same wattage format can be interchanged. However, please contact us to make sure.

The K at the end of color rating for each bulb stands for Kelvin. This is a measurement of the color temperature. The higher the Kelvin rating, the cooler (bluer) the color of light given off by the bulb. In general, the color given off by the 10,000K German is interpreted as being a perfect white color.

NOTE: Double ended bulbs should always be used with the UV shield (supplied). Your corals can suffer from excess UV radiation otherwise. The bulb should be handled carefully as well since it has no outer glass casing. Using soft gloves is a good idea to keep finger prints off bulb. This is during installation and replacement.

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
 




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13 Reviewers (69%) would recommend this

Overall Rating:

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“Worth every penny”
5.0

This bulb was the first that I have purchased for my nano. I usually try to go with the cheaper bulbs which saved me maybe $20-$30 dollars. This bulb was a major difference immediately. I would strongly recommend this if you want a super bright bulb with great blue tint. Everything in my tank res...Read More

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“Outstanding! - worth the money”
5.0

I have used numerous Halide bulbs during my years of salt water aquariums. These Geismann 20,000 bulbs are amazing!! Sure, they cost more than other bulbs but $36 more than a cheaper bulb is only $3.00 / month. I have used Ushio, XM, Hamilton and other bulbs. These make the others look sick. If...Read More

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“Bad bulb”
2.0

I bought two bulbs. The light being emitted from one bulb is yellow and the bulb is flickering. I was told by customer support to give it a couple of days to burn off the gasses. I may have to return it. It has been several days without change. The good bulb has a nice blue color.

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“Great bulb”
5.0

Bulb made an immediate difference over the off brand 14000k bulb I had been using. Corals which were browned out are now vibrant blues and greens. Tank looks awesome. It is expensive, but it's the best improvement for the money I've made to my tank. Highly recommend!

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“Great Color/Average Life Span”
4.0

I love the color of these bulbs. They will give you nine months of great coloration and growth from your corals. However, my first pair shifted spectrum at nine months and needed to be replaced. 9-12 months is the expected life span of HQI bulbs. Despite the shorter life span I believe these...Read More

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“love it”
5.0

I am extremely happy with this bulb. It has made huge difference in my tank with coral and acutely algae growth it has slowed algae down to where I can clean walls every few days and its still clear blue water...love the light would highly recommend

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“Dont Fit”
2.0

bulbs did not fit my fixtures, and kept slipping out.

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Overall, others give this:

13 Reviewers (69%) would recommend this

Overall Rating:

5.0  Star
 10
4.5  Star
 0
4.0  Star
 1
3.5  Star
 0
3.0  Star
 0
2.5  Star
 0
2.0  Star
 2
1.5  Star
 0
1.0  Star
 0
0.5  Star
 0