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Discussion Starter · #1 ·
I had a few hamilton 6.5k MH lights go bad on me and apparently this is happening a lot with the current batch they have. I can either wait 2 weeks to get new 6.5k that work (meaning no light for 2 weeks) or I can get them to send me 10k ones now. Is there a real difference in how plants grow under the different lights or is it just a visual thing? I have read that plants are fine between 6-10k but I just wanted to see if anyone here had any practical experience with the 10k. Thanks.
 

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It's a physical thing. If you could get a mix of 6500K and 10000K, that would be best. 10000K will give it a light blue tinge with MH, I've found. It tends to wash away a little of the colors. However, 6500K is a bit too yellow for me.

Sorry, but that doesn't really help you! Can they give you a credit for the bad bulbs? That way, you can go get ADA 8800K bulbs! :)
 

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Discussion Starter · #6 ·
well i have the 6.5k hamilton and they will replace them for free since I just bought them a month ago. But I can either wait 2 weeks till they get more in or get them replaced with 10k. I don't want to switch brands since I already bought them and can't get a refund just replacement. I had always heard that above 10k wasn't as useful for plants however I looked at the MHs on my dads tank yesterday and they are 15k and his plants grow great.
 

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For one thing the K rating is terribly innacurate, and doesnt describe the bulb spectrum that well. Plants see spectrum, not some somewhat arbitrary k-rating. The Iwasaki 15,000K (sometimes also listed as 14,000K) has more output in the photosynthetic spectrum of light than many other similar or lower K-rated bulbs, even ones that are higher wattage. I dont have spectral data for any hamilton 6500K's though so I cant compare them, but like I said the Iwasaki puts out more light than the 10,000K Hamilton does. Just goes to show how useless the K rating is.
 
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