# Metal Halide Bulbs



## imatrout (May 12, 2005)

Do you know if metal halide 10K bulbs work well for plants? I am really interested in those new Coralife Advanced Aqualights that hang on the tank. They only come with either 10K or a 20K bulb. My qustion is: Would 3 wpg of 10K light metal halide light grow plants as well, worse or the same as 3 wpg of power compact lights at 6.7K kelvin?

Thanks!


----------



## gnatster (Mar 6, 2004)

From 4200K - 10,000K most any bulb will grow plants fine. The biggest difference is the way the tank looks to your eye. Each different brand bulb will look a little different. So a 10,000K Iwasaki is going to look a little different then a 10,000K Coralife. Both however will grow nice plants.


----------



## AaronT (Apr 26, 2004)

I'm finding my 10,000K Ushio 175 watt bulbs to be on the yellow side. I'd go with a lower color spectrum if you can.


----------



## imatrout (May 12, 2005)

By lower, do you mean like 20K. I thought the lower the kelvin, the yellower the light. True?


----------



## david lim (Mar 30, 2004)

20000K would be straight blue like an actinic. Over time though they tend to clear up. I would recommend going to a reef store and looking at the bulbs that they use. They should be displaying different K temp bulbs on their reef tanks. That way you get a better idea of what the bulbs look like after they've burned in. Most 10000K bulbs I've had experience with get a little yellow. 13000K has a little blue tinge to it which is kind of nice and burn into a nice white. i have a friend that runs a 10000K 250W HQI MH with PCF actinic supplements over his planted tank. It looks pretty cool too.

David


----------



## AaronT (Apr 26, 2004)

imatrout said:


> By lower, do you mean like 20K. I thought the lower the kelvin, the yellower the light. True?


No, by lower I meant 5500K or so. I've seen gnatster's tank with those bulbs and the reds were much more pronounced. The reds in my tank get washed out by the yellow of the 10000K bulbs.


----------



## gnatster (Mar 6, 2004)

Here is where different bulbs by different bulb marketers/makers have different characteristics. 

Aaron says that the 5500K on my tank makes the red pop better then the 10,000K he is using. Well in theory 5500K should have a distinct warmish yellow/orange cast to them. Where a 10,000k should be very crisp and blueish. Being I run a 250W HQI and he has a 175W standard that in it's self would make a difference. Factor in mine are AquaMedic brand and his are Iwasaki and there is more differences. 

As David said, try to get to a reef store or two and check out what they are using. See what one catches your eye the most. Use that. Keep in mind the bulbs much over 10,000k begin to lose the reds in the spectrum that plants need.


----------



## jsenske (Mar 15, 2004)

10Ks can grow awesome plants. I've been using them for years. 8K is better in my opinion- just looks a lot nicer too- but 10Ks definitely work just fine.


----------



## frmrreefr (Jan 5, 2005)

I've got an XM 10k 250W SE over my 85 and it definitley looks white. A crisp, white that has not strayed into either the blue or yellow spectrum. 

Coming from a reef background, I was partial to the cool blue look of 15k bulbs but found out the hard way that it grows more algae than anything else. 10k bulbs are the happy medium between the warm yellows/oranges of the lower spectrum and the cooler blues of the higher spectrum. It also accentuates all of the colors of the fish and makes them "pop" so to speak....(the colors not the fish!) And it grows plants like gangbusters!


----------

