How much PAR is enough?

[reedman]

Thanks for all the info Boomer! I've got a little reading to do and then I'll pick the bulbs. I just wanted to best understand what the PAR measurements meant before basing a decision on the PAR rating. I'm glad I asked at this point, since I've learned a lot already.

Cheers all.
-Reed

 

[mojoreef]

Reed I am not sure but are you asking is thier a point at which corals cant handle any more light. If so the answer i yes. Dana had some interesting studies showing the point of deminishing returns. Corals do have internal methods to shut down thier photosynthetic process, when they reach a point of saturation and cna not handle the amout of oxygen being created.


Mike

 

[reedman]

Interesting Mike, but no. I was wondering if there was a relation between coral health and PAR that tails off at some point. For instance, if you can keep corals "healthy" with a bulb that puts out say 200 PAR. And a 300 PAR bulb make the corals grow 50% faster, have better color, etc. Then when you get to say a 400 PAR bulb the corals grow slightly faster than the 300 PAR bulb and look about the same. Diminishing returns for higher PAR beyond 300 in this example. And thus not much point in spending money on the higher PAR or basing your decision on it either.

I just wanted to understand how to factor PAR into the decision process (if I even should) for my new bulbs. Choosing a temperature is pretty easy for me, but choosing from within a temperature becomes a game of cost vs. value. I'm trying to figure value and PAR was one of the measures.

 

[Stircrazy]

Reed I am not sure but are you asking is thier a point at which corals cant handle any more light. If so the answer i yes. Dana had some interesting studies showing the point of deminishing returns. Corals do have internal methods to shut down thier photosynthetic process, when they reach a point of saturation and cna not handle the amout of oxygen being created.


Mike

Are we going to hit that point with artificial lighting though?

Steve

 

[WAVESHAUN]

I don't wanna highjack this thread, but on a related Q., what about 400DE Lamps?? Anyone?? Bueler... bueler...(Faris reference)

 

[mojoreef]

Sure it happens most every day Steve.

SHaun good to see you on board, I gues it would depend on what temp the bulbs were.


MIke

 

[Stircrazy]

Sure it happens most every day Steve.

MIke

I am not sure I understand, I have a higher amount of PAR going into my tank than most, but yet I am only 1/6 to 1/4 of that put out by the sun. Also when I coral is getting to much output from the algae inside it does it not reduce the amount of algae to a point where it isn't getting a overdose? hence the pretty colors due to a lack of algae inside the coral.

Steve

 

[WAVESHAUN]

Thanks Mike-

Krystal Star 400W Double Ended 10K (PFO)

 

[mojoreef]

Oh man Steve thats a question with a long tale, lol and really two seperate things.

I am not sure I understand, I have a higher amount of PAR going into my tank than most, but yet I am only 1/6 to 1/4 of that put out by the sun

Every coral has a point of deminishing return, to where it will stop its photo.. cycle, it doesnt matter if its in your tank or out in the wild. This cycle is base more on the zoox and how much it sugar (keep it simple) it is processing. So an example would be that with stronger light the cycle and point of deminishing return is of a shorter period. See if you can do a search on Dana riddles work on this, he had some great graphs and studies on it.
On the color thing, that is kind of a different animal. Zoox are not restricted to nutrient/food source just from light. Nutrients are absorbed through the tissue of the corals and made available, also the coral returns some nutrients as part of the photo... cycles to. In the case of less zoox = nicer colors, this is but one factor.
Low nutrient is a biggie, nutrients fertalize zoox.
The presence of the pigments are another.
UV is another (promotes protectorant pigments)
Color of the bulb, plays a big part.

Mike

 

[mojoreef]

Shaun I havent seen the testing on that bulb, but 10K at 400 watts and de sounds like a ton of par to me lol


Mike

 

[Stircrazy]

ya I realize there are the other factors also, but in two tanks with all those other factors the same, you can vary the amount of color with the light intensity (and hand in hand UV output). so what I am wondering if we leave all the rest out and assume for this topic they are constants, will the coral release algae as the light becomes more intense to protect its self from the excess O2?

Steve

 

[mojoreef]

Oh ya just make me stay on track,lol. heres the game. if the coral begins to produce to much oxygen it can cause the formation of hydrogen peroxide which will kill the coral. Corals do have enzymes to detoxify these oxygen forms,but if the ammount is to great the zoox will be exspelled. It is not really known if it is an operation done by the coral or the zoox. But this scenerio is a last blast type of thing. So to answer your question I would have to say no, possibly to a very small degree. You got to remember zoox have lifespans to and are exspelled constantly. Also what ever the zoox gives the coral,the coarl give back to the zoox in the form of carbon and nitrogen.

If your looking to reduce populations of zoox,look to nutrient limiting.


Mike

 

[moonpod]

Dana Riddle has done work on this. There is a point of photoinhibition and a point of no added benefit. I can't remember where the link is. As I recall, photoinhibition really can't be acheived with aquarium lighting, but no added benefit can be acheived.

I've seen several 400w DE setups. Color stability is a big time problem.

 

[WaterDogs]

I've seen several 400w DE setups. Color stability is a big time problem.

What do you mean by "Color stability" is a problem with 400w DE setups? On what size of tanks?

Dwaine

 

[moonpod]

color stability of the bulb, not the animals.

10k looks 5kish after a few months
20k looks 10kish after a few months.

They were on BIG tanks.

 

[Scooterman]

This is a nice subject, it can be talked about over and over. Fortunately, guys like to study these things for years & years, so at their expense, we can reap the rewards. The one thing the stands out to me is the variables, I'd imagine we are better aware of lighting needs as compared to a few years back, also the technologies continue to evolve. You have to admit, we do come up with some nice lighting systems, along with everything else, maybe not perfected but very much improved.

​

 

[jlehigh]

color stability of the bulb, not the animals.

10k looks 5kish after a few months
20k looks 10kish after a few months.

They were on BIG tanks.

Actually in my experience the 20K DE's after a few month (Both Coralvue and PFO) look more like 12-14K. I would not go as far as to say it's a stability issue since all bulbs have a burn in period where the bulb temp alters. The bulb temp of my 400W de's did not change after about 150 hrs of run time. (of course this is limited to the interpretation of my eyes and the reasponse from the life in my tank, which is good)

 

[mojoreef]

Hiya Moonpod

photoinhibition really can't be acheived with aquarium lighting, but no added benefit can be acheived.

Well those are really two different animals. the point of deminishing return for a coral and the light it get and uses is an everyday event, Studies have shown this on bulbs down to 175's. Photoinhibition is basically where the coral creates oxidents, ut its not just a factor of lighting. A coral can handle that most of the time with the production of D1 protien. Usually it become a problem and can get out of hand for a coral when thier are other stresses happening at the same time. Even that can be avoided still by the coral as corals usually get a wide variety zoox types, these different types of zoox can like high light, shaded light and even dim light. The coral that has a good population mix is usually the survivor.


Mike

 

[MikeS]

Dana Riddle has done work on this. There is a point of photoinhibition and a point of no added benefit. I can't remember where the link is. As I recall, photoinhibition really can't be acheived with aquarium lighting, but no added benefit can be acheived.

I've seen several 400w DE setups. Color stability is a big time problem.

I believe this is the article you are referring to?

http://www.advancedaquarist.com/issues/aug2004/feature.htm

the main point I got out of it was photoinhibition due to UV radiation....

MikeS

 

[mojoreef]

Try this one its has a bit more info.

http://www.cms.uq.edu.au/marbot/publications/pdffiles/litreviewtracey.PDF

MIke