XM 20K vs Ushio 10K color difference

[Diver_1298]

My metal halide bulbs were getting old and I decided it was time for a change.
I originally bought some Ushio 10K metal halides based on a couple of reviews that I had read. They suggested that the quality, PAR values and color were good for reef tanks and could be used for a wide variety of corals. I was not dissapointed. They have been working without problems with an excellent white, crisp color for longer than they really should be for a reef tank
So, after reading more reviews and studying some data provided by Sanjay Joshi, Ph.D. Advanced Aquarist's Online Magazine - Feature Article: Spectral Analysis of XM 15000K Metal Halide Lamps
I decided on an XM 250 watt 20K bulb. It actually had a higher PAR value than the XM 15K bulb on a magnetic ballast. Here is a side by side comparison of the bulbs. It almost makes the Ushio bulb look yellow.



Comments anyone?

Jim

[Boomer]

Looks nice but 20K is kinda to blue for me. Did you look at XM-10,000K with 137 PPDF. Almost twice the 20K @ 74 PPDF.

[Diver_1298]

Yes, I did think about that...
Right now I am not keeping any super light demanding corals, and I wanted something a little on the blue side. And after reading a couple of posts here from people who had bought the XM 20K bulbs I got the impression that they were not as blue as most of the other 20K bulbs on the market. That and the fact that they had a higher PAR value than the 15K bulbs is pretty much why I decided to go with them.
I guess time will tell if they work out for me. Right now I like the change in color, and I will be looking for changes in the corals. I lowered the canopy 3 inches last night


Jim

[Boomer]

Well, I guess tha is good reason