Kelvin VS Par

[reefshadow]

I'm not very tech savvy, so I have a quick question about lighting.

what is the general consensus on kelvin vs. par as it relates to the growth and colour of corals

i have a 240 mixed reef and had noticed that the output on my 1 year old 250 watt 14 k coralvues seemd pretty lame. i decided just out of curiosity to switch them for some of my old 10 k ushios. i was blown away by the difference in intensity, but not happy with the colours it rendered - not actual coral colour of course, but the way it looked to my eyes- i decided however to keep the ushios on and see if it made a difference in growth and coral colour. i haven't seen any difference in either though after a month.

is there a real advantage to more par, lower kelvin, or should i just put my dimmer coralvues back on, be happy, and plan to buy new lamps in the not too distant future :confused:

the corals seemed happy under the lower intensity, and i was getting good growth.

[LBCBJ]

Lower kelvins like 10k give you better PAR than higher kelvins, like a 20k. Some people claim their corals grow faster under the 10k's, but even if that's true I can't stand the color of a 10k. I love the Phoenix 14k, which is my personal favorite. I pick asethetics over coral growth...as long as they're healthy, who cares?

[Woodstock]

Hi Reefshadow!
I'm in the same boat. The light fixture I bought came with 10k Ushios and I had good coral growth but I didn't like the yellow look so I changed them for 14k Phoenix. This gave the tank a much more pleasing blue look IMO. Still had some coral growth just not as fast. My 14k are due to be changed out. I've been running them for almost a year now. I'll put the 10k ushios back in since they were barely used. I want to use them up rather than having them sit around but will probably go back to the 14ks next bulb change. Sorry, that's probably not answering your post but I'm just going to tag along.

Your tank looks very nice. I like your aquascaping!

You're from Central Washington, huh? Me too.:wave:

[reefshadow]

hi, Woodstock!

nice to hear from another ncw reefer! we are few and far between. i'm in wenatchee, let me know if you wanna do a frag exchange or something. thanks for the compliment.

i put the 14k back in. the colour rendering looks so much better, but just alot dimmer.

i thought maybe it was just me that thought the ushios were very yellow looking. i've had other 10k bulbs but they were much more white than yellow

oh well, i guess i can do without all those glitter lines.

[xtrstangx]

Kelvin and PAR do not directly correlate.

Generally speaking, 10K bulbs will have a higher PAR than 14K (and then 20K).

[boyooso]

I might be able to help?

I have run the 175w 10K ushios for 2 years now. The yellow hasn't bothered me though. But out of curiosity of what my new addition (bubble tip anemone) would look like under 14K I decided to buy the 175 14K hamilton. After a bit of research and a little concern over the lost PAR, I discovered the...

Iwasaki 175W SE 15K bulb .... taa-daa

Sanjay Joshi's review of 175w bulbs (http://www.advancedaquarist.com/2005/12/review)

I should add, after I received the 14K hamilton I installed it and wow, it was blue, but it was quite dim in comparison to the 10K Ushio. I left it installed for 2 days.

Then the new Iwasaki bulb arrived and I installed it(I am sure I stressed the Anemone :-( ). WOW, it is bright, much brighter than the Hamilton and brighter than the 10K ushio with more PAR than the 10K ushio. Incendently it measures much closer to 15K than the Hamilton does to 14K.

If I had to compare the Iwasaki to one of the other bulbs I would compare it to the ushio. It really looked NOTHING like the Hamilton.

After about 2 weeks with the Iwaski I do notice it has a very different color than the Ushio, It is much more blue, magenta, red than the ushio. But it is very white, it gives you those light shimmers, but not the deep actinic coloration. I have concluded that the hamilton has its look because it is so dark, not becuase the color temperature. And the Iwasaki is so white because it is so bright, not because of its color temperature.

I hope that helps.

Corey

[reefshadow]

wow, thanks. maybe i will try out the iwasaki for my next lamp purchase.

i like the price of the coralvues, but they just don't seem to last that long...

[Danfish]

I'm assuming you guys are talking MH lights right?

So if I were to be using T5s I could just mix 10k and 14k (and even Acintic) to get the best of both worlds, correct?

(just trying to folow the thread)

[reefshadow]

yah. i do supplement with actinic vho's, but the ushios still look really yellow to me. plus there's the fact that i am using 4 foot vhos over an 8 foot spread, lol. they were left over from my 75 gallon so i threw them in the middle. so i'm actually using the 2 250 watt14 k halides on the ends, 2 175 watt 12 k halides coupled with the vho's in the middle. i had put the ushios back on the ends and they looked yellow as all get out. with the 14k's back on the ends the tank looks evenly lit all the way across and the same colour.

[boyooso]

The only place I was able to find it was...

www.coralreefecosystems.com

Good Luck.

Corey