Changing to 14,000K MH bulbs

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IndyReefMan

Aquarium Advice Activist
Joined
Mar 3, 2005
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Indianapolis, IN
I've been using (2) 150W 20,000K MH (Coralife) on my 72 gal reef tank for a year so it's time to replace the bulbs. I've decided to change to 14,000K bulbs (Phoenix). Since I'm staying with the same wattage bulbs, do I still need to photoacclimate my tank?
 
No. You will notice a bit less blue crispness to the water, but your should fill out the yellow portion of the spectrum a bit. No photoacclimation is needed. Let me know what you think of the difference.
 
Actually it is the opposite.(right?) 6500 to 10K is the bright intense light. I think lando is saying stay with the same wattage and not going all the way to 6500 or 10k will not be enough change to bleach your corals.
 
Let me know what you think of the difference

AWESOME!... much brighter. I replaced one fixture with a 14,000K bulb and left the other fixture with a 20,000K bulb and ran them side-by-side for awhile so I could compare them. There is a substantial difference in brightness, which is exactly what I was looking for, and they're still very blue. Of course, they will probably shift a bit more to the white side as they burn in so we'll see. I struggled over the decision whether to go with the Phoenix (which I ultimately chose), or the CoralVue 14,000K MH. RC members had a LOT of great things to say about the Phoenix bulbs and it appears that their PAR is a bit higher, so I went with them.

Incidentally, I'm currently running these (2) 150w 14,000K along with 130w 10,000K PC and 130w 6,700K PC and I still have a nice blue tint to the tank... it's only yellow for a couple hours each side of the photoperiod because I have those PC lights come on before and go out after the MH bulbs. I'm running the 6,700K PC for a few SPS frags that I have near the top of the tank.
 
If I had some delicate pieces in my tank, I would acclimate them a bit. Maybe reduce the photo period for a week or two.

If his bulbs are old and then switching to a 14k, which I believe to be more intense than a 20k, it could be a bit of a surprise for the tank. Really depends on the bulb too though. 20k = 20k when comparing different bulbs.

Better safe than sorry though.
 
Personally I would treat it the same way as changing the intensity and use screen material. The shift from blue to a whiter bulb will be brighter visually but from my reading, the 14k has less PAR than the 20K. In all honesty, if using actinic for "viewing appeal", 6500-10000 would be a much better choice. The higher in K you get, the shorter the bulb life spectrum wise.

If you really want to do some interesting reading, do a google search on the name Dana Riddle.

Cheers
Steve
 
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