imatrout

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

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

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

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

david lim

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

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

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.