DE Bulbs: In your opinion, (and experience)

[OCDP]

I had to take out the Geismann 13k or 13.5k (I forget) It was too yellow by itself (no actinic supplements yet) So I put back in my Ushio 20k.

Question is.... I know it's probably an easy answer, but.. are higher K bulbs less intense than lower K bulbs? Now, my 20k is almost a year old.. so I know it would have declined in intensity. But, wow... what difference , the geismann is a good bulb and will be excellent when I get it in the Aqualight Pro, but the 20k is just so much less intense (the length of use could also contribute)

But dang.. my corals look a million times better under 20k. I would way rather use higher K bulbs, and have more colour.. as oppossed to lower K bulbs and increased growth. The colour is stunning! I missed you Ushio :razz:

[digital-audiophile]

Can't say I didn't warn you :p I had a Giesemann 13.5k SE and it was super yellow. (even with actinic supplimentation)

Seriously, go up to Oceans and buy an EVC 14K bulb. They are super bright and have a fantastic blue colour. If you recall their SPS tank they are using a 400W 14k EVC. :D I am using a 250W EVC 14k and I love it.

[OCDP]

Hmm, well the Geismann came with the aqualight pro.. so no complaints on my end. I'm intrigued by the EVC now... could you PM me the price ?? Also, do they sell them in 150w?

[digital-audiophile]

Sent you a PM. They amke them in all watts and temperatures.

[vanreefer]

I'm a 10K man myself... also use ushios they are super white (only look yellowish for 1 minute after they turn on) I suppliment with 260W of actinic 130W of new bulbs and 130W of 1 year old bulbs that way I get a dawn and dusk effect ie old bulbs on 1st then new bulbs an hour later then MH. plus I only have to replace 1 set oh CF's/year :)
I love the white and the growth
Dan

[Denis]

I just switched to 14.5k Giesemanns from 10k Ushios, I'm very happy.
Much whiter than Ushios.
I'm still using VHO actinics for the extra color.

[Jaws]

If you want intensity and blue color you have to go with 400W bulbs in my opinion. I'm running four 250W Geismann 20000K DE bulbs on a six foot tank and although I love the color, I miss the shimmer of the 10000K Geismanns. I was warned by my LFS too. Not that I don't like the color of the tank right now but I think 14500K bulbs would have been better. When my lights run out next year I think I'll upgrade to 400W 20000K's. They've got a nice blue color without losing any intensity IMO.

[smellsfishy]

from what i have experienced the 20k should at least appear to be more intense or brighter however the brand has a big thing to do with it as well. i have noticed in my tank that the different colors of corals have a different appearance under different k's example blue tips on my acro almostr glow when i have my supplimental lights powerglows (18k) florecents ( i know sacralige lighting for hardcore reefers)while the brown softys almost diappear, then with just my 14k's the opposite occurs browns stand out more. It's an optical conclusion.

[Fish]

A 20k will usually provide a more asthetically pleasing colour, but a comparable 10k bulb will be WAY brighter.

It depends if you are asking about what gives the more 'intense' colour or the more 'intense' lighting. If you are talking about how strong the lighting is, you are probably talking about PAR. A 10k bulb gives off more PAR than a 20k bulb will. To get that nice blue color on a higher k bulb, you are giving up radiation that the corals could be using for photosynthisis. Even if the tank doesn't look dimmer to the naked eye, a quantum meter can detect the difference. As an example, the 250w xm10k bulb on an icecap ballast has a PAR reading of 640. On the same ballast, the xm20k was measured at 270 - less than half the amount of photosynthetically available radiation!
I once almost fried my corals when my 70w 20k burned out and I put a 10k iwasaki in as a replacement. Now I have another 20k and I use that because I prefer the colour and I don't need a lot to light my 12" cube.


This thread on RC is what I used to make my 250w lighting decisions: http://www.reefcentral.com/forums/showthread.php?s=&threadid=254667

Sanjay's site is good too: http://www.reeflightinginfo.arvixe.com/index.htm

HTH,

Chad