Too much light??

[kipsix]

Is there such a thing as too much light? Can you actually give corals too much light?

[Rbacchiega]

Depending on the type of coral, yes. That's when you get into considering where in your tank you need to put the coral for it's lighting requirements ie, at the bottom, in the shade of some live rock etc.

[tang daddy]

you can cook any soft coral with too much light, even sps believe it or not....

It's called bleaching I have lost a few nice yuma's this way burnt a few species of sps like monti and deepwater.

[lorenz0]

i have bleached out a yuma from to much light. but it all depends on the coral. i know some of my mushrooms weren't to fond of my light upgrades and i had to have most of the bulbs turned off to aclimate them properly

[StirCrazy]

if you acclimate the coral to the new light properly, then no there is not such a thing as to much light, no matter what we do we will never come close to what the sun lays down on a reef.

If you bleach a coral don't throw it out as it will come back, but if you have proper water flow and use proper techniques to introduce your new light then you won't have a problem.

Steve

[Canadian]

Yes there is such a thing as "too much light." It is species dependent however. Photoinhibition is possible and varies dependent on the species of coral/zooxanthellae being investigated - essentially blasting corals with tons of light can be a waste of hydro. But excessive lighting can also produce some unique effects so "too much light" is a relative term depending upon your goals (growth, fluorescence, etc.)

Read here:

http://www.advancedaquarist.com/2007/3/aafeature1

[Myka]

Agreed. No such thing as too much light, just poor acclimation practises. ;)

if you acclimate the coral to the new light properly, then no there is not such a thing as to much light, no matter what we do we will never come close to what the sun lays down on a reef.

If you bleach a coral don't throw it out as it will come back, but if you have proper water flow and use proper techniques to introduce your new light then you won't have a problem.

Steve

[Reefer Rob]

Even Acropora can get too much light. If I try to go too long of a photo-period with 400w lights, some acros lighten, and stop growing...even with a long acclimation period.

[StirCrazy]

Yes there is such a thing as "too much light." It is species dependent however. Photoinhibition is possible and varies dependent on the species of coral/zooxanthellae being investigated - essentially blasting corals with tons of light can be a waste of hydro. But excessive lighting can also produce some unique effects so "too much light" is a relative term depending upon your goals (growth, fluorescence, etc.)

Read here:

http://www.advancedaquarist.com/2007/3/aafeature1

ahh yes, a waist of money yes, but not to much light which will fry the coral, it will just stop using it.

so basicly you have said there is to much light but you are not in the context of this topic, we are not talking about "how much can I get away with and I don't want to use any extra hydro whatso ever"

but rather will to much light kill my corals, I re read the article you listed and a few others and not one of them is saying that the lights we are using in this hobby will kill our corals if they are properly adjusted to the light.

Steve

[StirCrazy]

Even Acropora can get too much light. If I try to go too long of a photo-period with 400w lights, some acros lighten, and stop growing...even with a long acclimation period.

what kinda 400 watts you using? the Iwak (can't remember the spelling) had a tendency to lighten up corals, but I think it was from there spectrum not the intensity.

my reason for thinking this is my old light design put out 22% more PAR than the 400 Iwak but instead of it being at 6500K it was at 12300K.

Initialy things slowed down but after a week, my colors went deeper, growth exploded, in everything from mushrooms to SPS. I had to get rid of about 30lbs of live rock as my tank was being taken over by mushrooms.

Steve

[StirCrazy]

Also another thing to note, I have never been a fan of 400 watt bulbs, I think unless you have a tank that is 30" or more deep they are a waist of power, especialy when you can do a proper 250 watt HQI/Mogal set up that puts out more Par.

Steve

[Canadian]

Steve,

If you read the article I posted you would be aware that while "too much light" won't fry the coral it will certainly lead to photoinhibition. I don't see any point in providing more light than the organism can use unless the intention is to cause some potential color shifts.

What I've reported is not based on anecdotal experience or assumptions but is based on relatively sound research.

[StirCrazy]

Steve,

to cause some potential color shifts.



exactly.

[Canadian]

The italics around potential were lost in your quote Steve - and the research on PAR levels affecting coloration are equivocal with some showing that lower PAR produces greater fluorescence.

[StirCrazy]

The italics around potential were lost in your quote Steve - and the research on PAR levels affecting coloration are equivocal with some showing that lower PAR produces greater fluorescence.

in one form of green and a couple Orange.

the point is that I can take my PAR meter and put it 2" from a 250 watt HQI and it is still less par than Victoria gets in the winter on a rainy day.


all those charts on photo inhibition are great, but they are all missing one important piece of info (I just spent the last 2 hours reading and trying to find it) time, so if I shine this light on my corals how long until i reach this magical point?

this is very useful as what it would allow you to do is run some lower powered lights like T5's for the bulk of the day and then just have you MH come on for 2, 4, 6, or what ever time is required to reach the saturation point which could potentially save money.

I have been following these articles for years, I believe they started coming out in 02, but some of the others are 04. they all say the same thing and nothing at the same time. take this scenario for instance. you have a 30" wide tank, that is 18" deep and 12" wide (just picked that size as it is what I am building) I am going to run two T5's for actinic which will run 12 hours a day. I am looking at running a 250 watt SE bulb driven by an electronic HQI ballast. the bulb orientation will be in the middle of the tank front to back. and run 8 hours a day

Ok do you believe that if I take corals and put them all over that tank that they are all going to reach saturation? I would guess that it will be less than 10% of the tank is going to receive enough light to do that.

I enjoy reading the articles on line but remember that none of these have gone through peer review and that most of them are rehash of several older documents in the authors opinion. Not to say they are wrong, but we are only seeing a narrow chunk of info here. If you want to dig around there are several other good articles on lighting including a few on how to increase the amount of light in a tank with out reaching the saturation point by cycling the lights on and off for periods of time. this one formed the basis of the way I do new light acclimation and I have never seen better results. If I didn't have to buy a new computer as my old one had a melt down I would be able to give you links but they are lost to me and I haven't had the time to re find them.

another thing to consider, for the bulk of people who upgrade there lights have you ever heard anyone say "I have to much light" or "my coral growth slowed down when I put the 400 watt radiums on"?

when I started my last tank, lighting was a mystery.. Dana and those were not doing any reporting or anything at that time so we didn't even have basic articles to re-fur to.. at the same time I don't think it is a realistic set up that blasts a 400 watt iwasaki over a 12" deep tank, maybe I am wrong :mrgreen:

info on lighting has come a long way in the last 9 years which is good. but there are new things that are more important than, which light and do I have to much, like water flow. this is probably the most overlooked thing in reef tanks and the hardest to set up properly, but I see there are a few articles out on it now which is good.

Steve

[StirCrazy]

you can cook any soft coral with too much light, even sps believe it or not....

It's called bleaching I have lost a few nice yuma's this way burnt a few species of sps like monti and deepwater.

I hope you didn't throw them out from just being bleached, they come back from that.

Steve

[Canadian]

in one form of green and a couple Orange.

the point is that I can take my PAR meter and put it 2" from a 250 watt HQI and it is still less par than Victoria gets in the winter on a rainy day.


all those charts on photo inhibition are great, but they are all missing one important piece of info (I just spent the last 2 hours reading and trying to find it) time, so if I shine this light on my corals how long until i reach this magical point?

this is very useful as what it would allow you to do is run some lower powered lights like T5's for the bulk of the day and then just have you MH come on for 2, 4, 6, or what ever time is required to reach the saturation point which could potentially save money.

I have been following these articles for years, I believe they started coming out in 02, but some of the others are 04. they all say the same thing and nothing at the same time. take this scenario for instance. you have a 30" wide tank, that is 18" deep and 12" wide (just picked that size as it is what I am building) I am going to run two T5's for actinic which will run 12 hours a day. I am looking at running a 250 watt SE bulb driven by an electronic HQI ballast. the bulb orientation will be in the middle of the tank front to back. and run 8 hours a day

Ok do you believe that if I take corals and put them all over that tank that they are all going to reach saturation? I would guess that it will be less than 10% of the tank is going to receive enough light to do that.

I enjoy reading the articles on line but remember that none of these have gone through peer review and that most of them are rehash of several older documents in the authors opinion. Not to say they are wrong, but we are only seeing a narrow chunk of info here. If you want to dig around there are several other good articles on lighting including a few on how to increase the amount of light in a tank with out reaching the saturation point by cycling the lights on and off for periods of time. this one formed the basis of the way I do new light acclimation and I have never seen better results. If I didn't have to buy a new computer as my old one had a melt down I would be able to give you links but they are lost to me and I haven't had the time to re find them.

another thing to consider, for the bulk of people who upgrade there lights have you ever heard anyone say "I have to much light" or "my coral growth slowed down when I put the 400 watt radiums on"?

when I started my last tank, lighting was a mystery.. Dana and those were not doing any reporting or anything at that time so we didn't even have basic articles to re-fur to.. at the same time I don't think it is a realistic set up that blasts a 400 watt iwasaki over a 12" deep tank, maybe I am wrong :mrgreen:

info on lighting has come a long way in the last 9 years which is good. but there are new things that are more important than, which light and do I have to much, like water flow. this is probably the most overlooked thing in reef tanks and the hardest to set up properly, but I see there are a few articles out on it now which is good.

Steve

Here's a discussion where you'll find that photoperiod has no impact on photosaturation - the conclusion is that it is purely intensity dependent and has nothing to do with photoperiod. The link is not a peer reviewed journal article but the information is posted by a MSc. Marine Biology student. He notes that your assumption that photoperiod some how affects photosaturation is a commonly held myth within this hobby:

http://reefcentral.com/forums/showthread.php?threadid=1471682&highlight=photoinhibition

And here's a peer reviewed journal article showing that at some of the highest PAR values in tropical reefs the species of coral under investigation was not able to photoadapt (analogous to acclimating in an aquarium) to the high levels of light and exhibited photoinhibition at middday when the PAR levels were greatest (it also shows some other interesting things related to fluorescence at different PAR levels). Also note that the upper values of measured PAR in this study were around 1100 which are readily achieved in a typical aquarium with 2 x 250W MH:

http://www.aslo.org/lo/toc/vol_48/issue_4/1388.pdf


And for what it's worth I definitely agree that we need to pay more attention to flow in our aquariums and match it to our light intensities.

[StirCrazy]

Also note that the upper values of measured PAR in this study were around 1100 which are readily achieved in a typical aquarium with 2 x 250W MH:



where did you find this in the article?

If they were getting PAR that high from anything under a 1000w bulb, they were holding the sensor 2 to 4" from the bulb.

the highest output bulbs I have tested so far were SE AB 10K's running on a magnetic M80 ballast, at 12" of water and air (7" air and 5" of water) they were putting out just shy of 700, at a depth of 23" water and 7" of air they were putting out about 480 to 500. I have tested 4 400 watt setups and various other 250 watt (both DE and SE) and none have come close to these numbers except the 400 watt iwasakis, which were about 20 points lower.

Bulb testing the way it is done on the bigger boards is stupid and useless to us as it reports theoretical numbers, not what you will actually get. So yes I could see theoretically the ability to supply to much light, but in reality I don't think you or me will do it. I am going to have my bulbs more than 1" above the waters surface and I am going to have my corals more than 1" under the surface. If they happen to grow to the point where these is to much light then they will simply stop rising and spread out instead. come to think of it I had a digitata do this in my old tank, grew to about 1" under the water surface then tabled out. was beautiful, but it never slowed in growth and I would be willing to be its growth could have been measured in oz/day. but at any rate I don't believe it is something we have to worry about in a practical application.

Now lets stop scarring everyone from adding to the discussion, if we want to keep going back and forth we should get a coffee :mrgreen:

Steve

[kipsix]

Now lets stop scarring everyone from adding to the discussion, if we want to keep going back and forth we should get a coffee :mrgreen:

Steve

Well, I only started this thread as I was struggling with 2, 4, 6 and 8 Bulb T5HO. Curious whether you could effectively kill your coral with too much light. Now I have heaps of reading to do. :biggrin:

Once I have finished reading all the links and studies.... thanks for your replies.

[StirCrazy]

Well, I only started this thread as I was struggling with 2, 4, 6 and 8 Bulb T5HO. Curious whether you could effectively kill your coral with too much light. Now I have heaps of reading to do. :biggrin:

Once I have finished reading all the links and studies.... thanks for your replies.

In my opinion you could never kill coral from T5's, the light we are talking about is high wattage MH in shallow systems and even then it won't kill them, but at worst from what I have taken out of the last few articles and several others I have read, is slow down there growth from an optimal rate and waist money.

Steve

[kipsix]

I kind of figured you it was unlikely to fry coral with T5's but I wasn't too sure, thought I'd throw it out to the experts and see what the ruling was.

Will it matter if the tank is only 16" deep, and I cram 8 bulbs over it though? Probably going to be mostly softies and LPS.

[Canadian]

You could certainly get some bleaching of even Acropora sp. at 16" depth with 8 HO T5s - especially if not acclimated properly. And especially if a quality fixture with active cooling is used.


Steve,

That quote you were asking about isn't from the article. The PAR of 1100 is from the article but the portion about 2 x 250W MH producing this comes from Apogee measured values from a hobbyist's tank. While 1 250W MH produces the values you've reported the cumulative effect where they overlap with 2 x 250W MH could certainly produce that level of PAR at several spots in the tank - especially with a high quality reflector. For comparison see the picture below where 6 x 39W HO T5s in a crappy Tek light produced the PAR levels seen in the picture:

http://i85.photobucket.com/albums/k72/jartanyon/par.jpg

Fijiblue, the same hobbyist who was running the T5s in the picture above decided to try MH again with 2 x 250W MH over that same tank and found he was getting over 1100 PAR at the surface.

[StirCrazy]

Ok, I agree with that kinda of output in the air at a couple inches. When I did my testing on my tank I did that then I started at 6 or 7" below the surface where it had dropped off from around 1100 to about 700, so it does attenuate quite a bit when you bring water and depth into play.

yes, VHO, PC, even NO will bleach a coral if it is not acclimated properly, I am assuming that the acclimation is proper and we are not dealing with that.

Steve