Too much light??

[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]

Originally Posted by Canadian

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]

Originally Posted by 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.

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

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]

Originally Posted by 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.

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

Steve

[Canadian]

Originally Posted by StirCrazy

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

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/showth...hotoinhibition

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]

Originally Posted by Canadian

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

Steve

[kipsix]

Originally Posted by StirCrazy

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

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.

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

[StirCrazy]

Originally Posted by kipsix

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.

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