light spectrum and coral growth?

MaximumPuffer · 08/30/2006, 02:12 AM

I've been researching light spectrum and coral growth for a while here and other places on the net and by talking to people at my local fish store. Everyone i talk to seems to tell me something different about what spectrum corals need for photosynthesis. Most of my research on the internet leads me to beleive that its the blue spectrum 400-550 nm that zooxanthellae photopigments absorb to allow photosynthesis and thus stimulate growth in corals. This however is opposite of what the guy at my local fish store tells me. He went on to tell me that I wont get any coral groth from using only actinics on my tank and that they are only for looks.

P.S. Though I do not have that much for coral (a small colony of clove polyps) I will say that their growth exploded after i replaced my old white ligthing system with two URI 110 watt VHO Actinics. I also love deep ocean look

So can anyone say for sure what the deal is?

MaximumPuffer · 08/30/2006, 04:48 PM

no one can answer my question?

chopsuey · 08/30/2006, 05:16 PM

I canâ€™t answer you question but I heard the same thing from my LFS. The blues and actinics are for making the tank look more pleasing to the eye and not so washed out from the 10-20k MH. Gives the tank a more colorful effect but does not benefit corals at all. And that they are used for dusk or (lunar) light to complete the daylight cycle. I am just as

as you are

Charlie Davidson · 08/30/2006, 05:26 PM

Don't trust "your" LFS chopsuey!! also-- IMHO you can't beat MH..
Many do give peaks in the 420-450 range! (Like artinics)

bertoni · 08/30/2006, 05:57 PM

Most of the time, actinics are for looks because the rest of the lighting system is more efficient and puts out more light, but that depends on the setup. The frequency response of the various microbes (usually zooxanthellae) in the animals we keep is determined by a number of factors, and these organisms often have secondary pigments that allow it to use a wider range of frequencies.

This page discusses photosynthesis, as a quick intro:

http://www.emc.maricopa.edu/faculty/...BioBookPS.html

There are various books, etc, that might be useful if you want more details. Perhaps the best place to start is what type of setup you want to have, or do have.

WarrenG · 08/30/2006, 09:05 PM

While scuba diving in places like Fiji with lots of SPS corals I've noticed that they are mostly in the first 15-50 feet of water where the light is blue'ish, but not nearly as blue 2 VHO actinic with 2 VHO white lamps. Most of the clownfish and their anenomes are in the first 5-15 feet of water and the light is even more white. VHO's that are 50/50 actinic/white are more blue than what I usually see in the first 40-60 feet of water in the South Pacific and the Caribbean.

If you used all VHO actinics that would be similar to the light found below 100 feet deep, and not many of the corals we keep are found down there in the wild. Light levels are relatively low too. Down there it's mostly sponges and some soft, filter feeding corals. Virtually none of our reef tank fish are down there either.

Dr. JMadscientist · 08/30/2006, 09:38 PM

MaximumPuffer

Here is the breakdown...Actinics peak at 420 to 460 nm which is a blue light. Photosynthisis happens in this section. Mostly all light bulbs emit a certain amount in this range. Actinics are purely that, but are not that intense. A 6700k bulb emits more of this spectrum even though it visably looks yellow. 20k's produce less even though they look more blue.

Actinics can help for growth, but are not as effective as a daylight bulb. Hope this helps.

kwirky · 08/30/2006, 10:18 PM

Theoretically, corals photosynthesize best under two nanometer light ranges (can't remember which ones exactly right now). But advanced aquarist did a test and found that colour spectrum did little for photosynthesis. An equivelent PAR 6700 bulb compared to a 15000 bulb photosynthesizes the same. Overall, it's all aesthetic. The blue is only real important if you're trying to bring out deep colours from SPS coral, since you're blasting them with ultraviolet, and the colour pigments are their protection from the UV light.

I, myself, prefer "shallow" colour temperature, like 13000 colour temperature.

If you're comparing flourescent lighting, bulbs are not the same manufacturer to manufacturer, and MH lighting needs a lot of research too.

Here are two links to help you with your research:

http://www.advancedaquarist.com/2002/2/aafeature

http://www.reeflightinginfo.arvixe.com/ requires Internet Explorer

rickh · 08/30/2006, 11:09 PM

I switched from 1/2 actinic 1/2 daylight to 2/3 actinic 1/3 daylight. The coral glows and is growing fine. R

08/30/2006, 02:12 AM	#1
MaximumPuffer Registered Member Join Date: Aug 2006 Location: Victoria British Columbia Canada Posts: 18	light spectrum and coral growth? I've been researching light spectrum and coral growth for a while here and other places on the net and by talking to people at my local fish store. Everyone i talk to seems to tell me something different about what spectrum corals need for photosynthesis. Most of my research on the internet leads me to beleive that its the blue spectrum 400-550 nm that zooxanthellae photopigments absorb to allow photosynthesis and thus stimulate growth in corals. This however is opposite of what the guy at my local fish store tells me. He went on to tell me that I wont get any coral groth from using only actinics on my tank and that they are only for looks. P.S. Though I do not have that much for coral (a small colony of clove polyps) I will say that their growth exploded after i replaced my old white ligthing system with two URI 110 watt VHO Actinics. I also love deep ocean look So can anyone say for sure what the deal is?

08/30/2006, 05:26 PM	#4
Charlie Davidson Registered Member Join Date: Dec 2003 Location: Deltaville , Va Posts: 10,977	Don't trust "your" LFS chopsuey!! also-- IMHO you can't beat MH.. Many do give peaks in the 420-450 range! (Like artinics) __________________ Richmond Reef Club Current Tank Info: Doing without for a while :)

08/30/2006, 05:57 PM	#5
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	Most of the time, actinics are for looks because the rest of the lighting system is more efficient and puts out more light, but that depends on the setup. The frequency response of the various microbes (usually zooxanthellae) in the animals we keep is determined by a number of factors, and these organisms often have secondary pigments that allow it to use a wider range of frequencies. This page discusses photosynthesis, as a quick intro: http://www.emc.maricopa.edu/faculty/...BioBookPS.html There are various books, etc, that might be useful if you want more details. Perhaps the best place to start is what type of setup you want to have, or do have. __________________ Jonathan Bertoni

08/30/2006, 04:48 PM	#2
MaximumPuffer Registered Member Join Date: Aug 2006 Location: Victoria British Columbia Canada Posts: 18	no one can answer my question?

08/30/2006, 05:16 PM	#3
chopsuey Registered Member Join Date: Aug 2006 Location: Oregon Posts: 374	I canâ€™t answer you question but I heard the same thing from my LFS. The blues and actinics are for making the tank look more pleasing to the eye and not so washed out from the 10-20k MH. Gives the tank a more colorful effect but does not benefit corals at all. And that they are used for dusk or (lunar) light to complete the daylight cycle. I am just as as you are

08/30/2006, 09:05 PM	#6
WarrenG Registered Member Join Date: Jun 2003 Location: Sunnyvale, CA Posts: 738	While scuba diving in places like Fiji with lots of SPS corals I've noticed that they are mostly in the first 15-50 feet of water where the light is blue'ish, but not nearly as blue 2 VHO actinic with 2 VHO white lamps. Most of the clownfish and their anenomes are in the first 5-15 feet of water and the light is even more white. VHO's that are 50/50 actinic/white are more blue than what I usually see in the first 40-60 feet of water in the South Pacific and the Caribbean. If you used all VHO actinics that would be similar to the light found below 100 feet deep, and not many of the corals we keep are found down there in the wild. Light levels are relatively low too. Down there it's mostly sponges and some soft, filter feeding corals. Virtually none of our reef tank fish are down there either.

08/30/2006, 09:38 PM	#7
Dr. JMadscientist Moved On Join Date: Jul 2005 Location: C-ville Posts: 327	MaximumPuffer Here is the breakdown...Actinics peak at 420 to 460 nm which is a blue light. Photosynthisis happens in this section. Mostly all light bulbs emit a certain amount in this range. Actinics are purely that, but are not that intense. A 6700k bulb emits more of this spectrum even though it visably looks yellow. 20k's produce less even though they look more blue. Actinics can help for growth, but are not as effective as a daylight bulb. Hope this helps.

08/30/2006, 10:18 PM	#8
kwirky Registered Member Join Date: May 2006 Location: Calgary, Alberta, Canada Posts: 42	Theoretically, corals photosynthesize best under two nanometer light ranges (can't remember which ones exactly right now). But advanced aquarist did a test and found that colour spectrum did little for photosynthesis. An equivelent PAR 6700 bulb compared to a 15000 bulb photosynthesizes the same. Overall, it's all aesthetic. The blue is only real important if you're trying to bring out deep colours from SPS coral, since you're blasting them with ultraviolet, and the colour pigments are their protection from the UV light. I, myself, prefer "shallow" colour temperature, like 13000 colour temperature. If you're comparing flourescent lighting, bulbs are not the same manufacturer to manufacturer, and MH lighting needs a lot of research too. Here are two links to help you with your research: http://www.advancedaquarist.com/2002/2/aafeature http://www.reeflightinginfo.arvixe.com/ requires Internet Explorer

08/30/2006, 11:09 PM	#9
rickh Registered Member Join Date: Aug 2005 Location: Lost_in_Michigan Posts: 1,306	I switched from 1/2 actinic 1/2 daylight to 2/3 actinic 1/3 daylight. The coral glows and is growing fine. R