PDA

View Full Version : What does CCT and ppfd mean in Sanjays reports?


Doubledown
06/13/2006, 01:57 PM
What do these represent and what do they mean for the corals?

Also, what difference do spikes at different parts of the spectrum mean for corals?

I currently have PH14ks which show a huge spike around 450 nm and some smaller ones at 550 and 590. The XM 10ks that seem to be very popular have a primary spike around 420 and three later 550, 580 and 590. What is better for growth and color?

With all that info, how does VHO actinic change or effect corals.

Thanks

SunnyX
06/13/2006, 02:07 PM
CCT: Color on kelvin scale
ppfd: Usable light or PAR, Higher is better.

The Pheonix 14k's you currently have are excellent bulbs and you should have no need to switch. The 10K xm's are great but are a tad too yellow and overpowering for some people.

RichConley
06/13/2006, 03:08 PM
As to spikes, there are certain ranges of light spectrum that plants photosynthesize. PAR doesnt take that into account. 2 bulbs with the same PAR, 1 with it all in those specific spikes, and 1 with it averaged, the one with the spikes would provide better growth.

I can't remember the exact wavelength ranges that corals do best with.

Doubledown
06/13/2006, 03:17 PM
Ok. The PH14ks show PPFD of 88 and CCT of 0. The XM10k PPFD 109 and CCT 7026. The AB10K ppfd 104 and cct 8225.

Does this mean that the AB bulb will appear bluer than the XM? Or that the true color emitted from this supposed 10K bulb is really closer to 7K on the XM and 8.2K on the AB bulb?

Does this also mean that the XM bulb will provide more usable light for the corals than any of the others?

At what point does the usuable light (PPFD/PAR) provided by a bulb exceed the amount a coral can take in? To put it another way, what is the minimum required PPFD score for corals (SPS) to grow and maintain colors?

I am still confused. Too many choices (although I do appreciate the nod for keeping the PH14ks).

sfsuphysics
06/13/2006, 03:30 PM
Does this mean that the AB bulb will appear bluer than the XM? Or that the true color emitted from this supposed 10K bulb is really closer to 7K on the XM and 8.2K on the AB bulb?

Don't think either bulb will be "blue" at most you might get a white out of it. But the CCT is a mathematical formula that calculates the closest color temp to what spectrum is given, now with spikes in the blue range (mid 400's) that tends to pull that color temp closer to the higher temp range. The fact the XM10k has a 7026 CCT definately shows a more yellow look to it.

The reason the bluer bulbs (14kK+ sometimes even 12kK) show zero is because there is no accurate color temp for it since it's mostly in the blue.


At what point does the usuable light (PPFD/PAR) provided by a bulb exceed the amount a coral can take in? To put it another way, what is the minimum required PPFD score for corals (SPS) to grow and maintain colors?

Well I think its safe to say that you'd be hard pressed to give TOO much light... atleast if the coral is already used to it, there are many deeper water corals that don't like bright lights, not to mention a coral that's been under 20kK bulbs (great for nice coloring and decieving potential buyers, but horrid light energy) can easily be bleached to death if you blast it with too much light.
here's a chart from Sanjay showing sunlight
http://www.advancedaquarist.com/2005/8/aafeature_album/figure-4.gif
as you can see even at 10 meters down the PPFD is over 600, now compare that to what those bulbs put out and you'll see that you should be fine as far as not putting too much light.

End result though is that corals can accept a huge range of lighting conditions, some might keep corals under 400w bulbs, some might keep the exact same corals under 175w bulbs with success. The question is do you want to grow them as fast as possible? if so go with a yellower bulbs. Or do you want to enjoy them from an asthetics standpoint primarily (then go with bluer bulbs).

Doubledown
06/13/2006, 03:53 PM
I want it all I guess :).

I want both good growth and a pleasing to the eye appearance. For me, that pleasing to the eye appearance is more blue, but can this be obtained with the use of actinic VHOs?

Do actinic VHOs provide any PAR? What sort of CCT or wavelengths do these spike at?

Should I just use the trial and error method for picking bulbs? I have the 14ks, but want better growth. Should the next step be to a 12k or to a 10k?

Man I love this site! Thanks all for the info.