10,000K or 20,000K MH?

[greenmaji]

Thanks steve-s I really thought I was reading something into what you were saying that wasnt there.. In other words.. I really thought I was off my rocker there for a few..
It seems that all types of lighting perform better at lower Kelvin.. in other words it would be easier to get what the coarls need lighting wise if astetics where ignored, that of course is a little bit on the silly side for a home aquarium.. maybe a business growing out coarls or frags, or a propgation tank at home would make more sence.. thanks for the information.. it's changed my ideas about lighting reef aquaria quite alot..

WOW.. 03 is doing nada for the coarl photosyntheticly.. that really contradicts some advice Ive been getting (not all mind you) lately..

 

[steve-s]

WOW.. 03 is doing nada for the coarl photosyntheticly.. that really contradicts some advice Ive been getting (not all mind you) lately..

A little too literal I think and mabye my last post a little too general. Photosynthesis peaks at 420 nm which is where actinics generally run at (420-430 nm) but corals require a much wider full spectrum to perform proper photosynthethis. Actinics contribute to intensity for sure but not always in the way we want for coral growth or geared towards specific corals kept. To put it in better perspective, the type/kelvin of the lighting provided should be specific to the corals kept.

Copied from a Thiel article....

Chlorophyll a 420 and 660 nanometers
Chlorophyll b 435 and 643 nanometers
Chlorophyll c 445 and 465 nanometers
Chlorophyll d 450 and 690 nanometers

Beta carotene 425, 450 and 480 nm
Alpha carotene 420, 440 and 470 nm
Luteol 425, 445 and 475 nm

Phycoerythrins 490, 546 and 576 nm
Phycocyanins 618 nm
Allophycocyanin 650 nm

In terms of MH use, more commonly these lights are used for SPS and clams which are higher up in the reef. They require heavier use of lighting in the "day" spectrum or closer to 6500K. Once those needs are met, the actinic or blue is added to "wash" the yellow out making it more visually appealing.

Now with primarily soft/LPS tanks, actinic lighting becomes somewhat more important as does less yellow in the bulbs. These coral being deeper water species overall, they require less "day" spectrum and slightly higher K's. This is where the use of higher K bulbs becomes more advantageous. If you take your average hobbiest, often coral species are mixed in the tank (SPS/LPS/soft) where they are not found in the wild. It becomes necessary to try providing a "middle of the road" type lighting scheme that provides for all types kept. If a tank is more species specific, a more exact lighting scheme becomes advantageous.

There are definately arguements for and against the "need" of actinic use. Even the more commonly recognized experts in the hobby rarely agree on it. Some say their use (or overuse) is harmful & others say it's necessary. So far I don't think I've run across anything conclusive to one side of the argument or the other. You?

Cheers
Steve

 

[IndyReefMan]

Actinic lighting is purely ascetic, there is little to no benefit to photosynthetic life other than added light intensity. Tanks without 03 supplimentation are no worse or better off without it.

The respected author, Robert M. Fenner, states in his book "The Conscientous Marine Aquarist" that actinic lighting is more for the aquarist than the corals and further implies that actinic lighting does little or nothing for coral growth or health. I have read a number of books on reef keeping but this is the only book that I can recall specifically addressing the benefits/non-benefits of actinic lighting.

 

[IndyReefMan]

Copied from a Thiel article....
Quote:
Chlorophyll a 420 and 660 nanometers
Chlorophyll b 435 and 643 nanometers
Chlorophyll c 445 and 465 nanometers
Chlorophyll d 450 and 690 nanometers

Beta carotene 425, 450 and 480 nm
Alpha carotene 420, 440 and 470 nm
Luteol 425, 445 and 475 nm

Phycoerythrins 490, 546 and 576 nm
Phycocyanins 618 nm
Allophycocyanin 650 nm

Steve-- Any idea which of these ranges the 20,000K MH bulb will be strongest in. Maybe I can keep my 20,000K MH, get rid of my actinics and replace them with 6,700K PC. Then, I would have 2 x 150 watt 20,000K MH, 130 watt 10,000K PC and 130 watt 6,700K PC. It seems that I would have a very broad spectrum of light for my mixed reef, albeit stronger in the cooler color light.

 

[greenmaji]

Thanks again steve..
My thoughts were that deeper water species like mushrooms and such would be able to use 03 more then say LPS or definatly SPS coarls..
But it seems you covered that in your post.. good show

Now with primarily soft/LPS tanks, actinic lighting becomes somewhat more important as does less yellow in the bulbs. These coral being deeper water species overall, they require less "day" spectrum and slightly higher K's. This is where the use of higher K bulbs becomes more advantageous.

IndyReefMan...
From looking in your sig. it seems like this might be your situation..
in other words according to what steve just posted you might be better off with some higher K bulbs then 6500K if more light would be advantagious..
or of course.. your 03 bulbs might be doing some of your coarls some good..

 

[steve-s]

Steve-- Any idea which of these ranges the 20,000K MH bulb will be strongest in.

A majority of the output would be in the 380-475 nm range. There wll be some output in the higher nm area but minimal.

Maybe I can keep my 20,000K MH, get rid of my actinics and replace them with 6,700K PC. Then, I would have 2 x 150 watt 20,000K MH, 130 watt 10,000K PC and 130 watt 6,700K PC. It seems that I would have a very broad spectrum of light for my mixed reef, albeit stronger in the cooler color light.

Not a bad idea really. It would at the very least balance the visual blue color you see. Personally I wouldn't use actinic with the 20K, overkill IMO. The only drawback I see is if you use a dawn/dusk light timed scheme, the PC's will eventually look very yellow once burned in and can be very unappealing visually.

Cheers
Steve

 

[IndyReefMan]

Maybe I can keep my 20,000K MH, get rid of my actinics and replace them with 6,700K PC. Then, I would have 2 x 150 watt 20,000K MH, 130 watt 10,000K PC and 130 watt 6,700K PC. It seems that I would have a very broad spectrum of light for my mixed reef, albeit stronger in the cooler color light.

Not a bad idea really. It would at the very least balance the visual blue color you see. Personally I wouldn't use actinic with the 20K, overkill IMO. The only drawback I see is if you use a dawn/dusk light timed scheme, the PC's will eventually look very yellow once burned in and can be very unappealing visually.

Well, I did it and it looks GREAT! When you mix those different colors together the intensity of the 20,000K MH balances out the 6,700K and 10,000K PC very nicely. It looks cooler than 10,000K, yet warmer than a 20,000K. A very nice look. The only drawback that I have seen so far is the color does look very yellow before the 20,000K MH come on since I have the PC come on before the MH, but I expected that. Right now, I have the 6,700K PC turn on first. One hour later, the 10,000K turn on. One hour after that, the 20,000K MH come on. At dusk, I have the MH go off first, then 10,000K, then 6,700K.

Steve-- In the set-up that I have described, do you have any recommendations on photoperiod of each? Right now, I have the MH on for 10 hours, 10,000K for 12 hours, 6,700K for 14 hours. Perhaps I should shorten the time between lights coming on to one-half hour instead of one hour. This would shorten the total photoperiod from 14 hours to 12 hours. It would also shorten the time that just the PC are on to minimize the time that I have the yellow look before the MH come on.

 

[steve-s]

Nothing wrong with the length of your photoperiod at all. The only variation I would recommend is swapping the times of the 6700 and having the 10k come on first. You'll still get that yellow tinge but much less than the 6700.

Cheers
Steve

 

[greenmaji]

Well, I did it and it looks GREAT! When you mix those different colors together the intensity of the 20,000K MH balances out the 6,700K and 10,000K PC very nicely. It looks cooler than 10,000K, yet warmer than a 20,000K. A very nice look.

Sounds like someone needs to share some pictures...
That sounds great!

 

[runway1]

I am very worried this will be too blue for my tastes. Appearance aside, is there anything detrimental about using 20K bulbs?

One of the lfs's I frequent has a 3x250w, 20k set up on a large display tank. It looks awesome. I was really surprised that all were 20k bulbs. I expected a very blue look but not at all. I'm going to try a pair of 20k's myself.