TOO MUCH IS NEVER ENOUGH ???

[TXnano]

Being a new member and a poor college student, some people may not take this seriously, but i am going to post anyway. I am a Agronomy major and i basicly study how plants grow. The thing i have noticed is the simularities of plants and corals. The photosnythesis theories are closely related. So here it is. I remember reading about a man on the net that kept a clown and an anenome alive in a nano at his office desk for 3 years. The kicker is that he was using stock flouresent lighting on the tank. I saw this story and thought how stressed and bleached that anenome must have been. But it could make sence. If the aquarium industry used to breed/propagate corals/inverts under less intense lighting, then it would make sence that they would be acclimated to a lesser light source. So when you bought a tank.. just say 20 years ago... the top of the line thing was flouresent lights, which probably cost a bit of money at the time. As the industry developed better light over the years they had to sell to stay afloat so they acclimated newly propagated corals to higher lighting sources... such as PC's and HID's. Well i will agree that SPS corals need higher light than softys, but the question is how much is enough? In the ocean corals receive most of their light from 10am to 2 pm. A mear 4 hour period. At that time of day light intensity is about 10,000 candle/ft2 which is close to a 10,000K MH. So is keeping coral under a 300W 10,000K bulb for 10 hours too much. Honestly i do not know... nor do i have the equipment to find out. But the reason i wrote this was to raise the question and maybe someone with more monitary support than myself could research it and find out.
The chart i attached breaks down like this.
1.Resperation is the nutrient use by an oganism and therefore growth. The resperation of a plant is not effected by light whatsoever and remaines constant.
2. As light intensity increases so does photosynthesis until the light saturation point is reached.
3. At the light saturation point, no matter how much light more is aplied no greater amount of photosythesis will take place.
4. At the light compensation point an organism will live but not grow... so Photosythesis is equal to Resperation.
5. Where Photosynthesis < Resperation, the organism will use all its reserved nutrient/energy and slowly die.
6. Where Photosynthesis > Resperation, the organism will grow and store energy.
SO... wouldnt it be great to know just how much light is enough without spending hundreds of dollars on excessive lighting... that is my goal.
I will be happy to try to answer any questions you may have.

 

[J Crew]

good question to discuss. post this over at reefcentral too: http://reefcentral.com/forums/index.php?s=

i'd like to see what others have to think about your thoughts. peace

 

[Anonymous]

Three questions:
1, "the ocean corals receive most of their light from 10am to 2 pm. A <mere> 4 hour period. "
Where do you get the 4 hour number?

2, "10,000 candle/ft2" and "300W <MH>"
Do you mean a 10kcd.ft^2 is about the same as the output of a ~300W MH?

3, "10,000K" The number I ususally see is much less for sun spectrum near the surface of the ocean... where did you get the number from?

Some comments... the light compensation point is pretty high for some coral. Furthermore, we don't want to use more efficient lighting (lower Kelvin bulb that give tank a yellowish look but with more PAR), so more electrcity is used than necessary.

The photosynethetic model works for the algae that live in some of the coral. The growth of a coral involve more parameters, such as calcium and availability of food (coral is animal, afterall) in form of phytoplankton and zooplankton.

 

[TXnano]

First of all i was trying to get people to tell me what they think of this theory, so thank you David.
the 4 mere (thanks for the spell check) hours are the hours between 10 am and 2 pm. They are the hours when the sun is the most intense throughout the day. Kelvin rateing on a bulb such as 10,000K refers to the color of the bulb not the itensity of it. The intensity is in wattage. How many watts is the sun.... who knows? The idea was to ask how many watts of light/intensity is enough for a coral to reach the peak of photosynthesis.
To your second question.. like i said I dont know the wattage of the sun so we measure in candles/ft2, which is about 10000 lumens/ft2 from 10am to 2pm.... i dont know what that would translate into in wattage because the amount varies with the kelvin temperature. In pure white light it is about 281 lumens / watt. so 10,000 lumens would be 36watts / ft2. But as we both know light doesnt come in pure white, it has many colors and is filtered out by the ocean until we have violet and this is off subject.
To your comments.... Kelvin is the color of the bulb not the intensity. And as for corals.... i do not know about them that well but i was suggesting an experiment. Such as same tank.... same food... just adding a bit of shade cloth over part of the tank periodically and messuring light intensity under it. When a certain coral... say SPS stops growing at the same rate as the other you will know you broke the light saturation point. SO instead of people spending hundreds on 300W 10,000K MH, they could grow corals at the same rate with 100W 10,000K PC's. That was the point

 

[Anonymous]

TXnano

the top of the line thing was flouresent lights, which probably cost a bit of money at the time. As the industry developed better light over the years they had to sell to stay afloat so they acclimated newly propagated corals to higher lighting sources...

I'm not sure how valid your logic is here. There are many species of corals that would not live in captive systems not so long ago. Current lighting systems, along with other things have allowed us to keep them. The corals were not acclimated to live in more light, we became able to provide them with more light to allow them to live!

It's impossible to reach this saturation point you speak of with many SPS corals, at least without melting your tank or boiling the water. Think about how much light an acropora growing under an average of 2' of water in the equator gets.

Cheers
Jim

 

[smlacy]

I've heard it stated that the incident radiation of the sun at sea level is about 1000W/m^2. That translates into about 93W/ft^2.

I've thought about this quite a bit, and been involved in similar online discussions, and the end result is never as absolute as you'd like. The factors you'll hear a lot of debate about:

- How much does the water absorb the light?
- How much light escapes the aquarium?
- Even if we could simulate the sun, would we want to and why?
- Aquariums are synthetic systems, and emulating nature isn't always the best thing to do.

Something that I always ponder is that most of the creatures that we keep in our aquariums are used to living in 5-50 feet of water, not the measly 5-30 inches that we typically give them. This factor alone makes figuring out whats "right" for aquarium systems very difficult.

Steve

 

[Anonymous]

Something that I always ponder is that most of the creatures that we keep in our aquariums are used to living in 5-50 feet of water, not the measly 5-30 inches that we typically give them. This factor alone makes figuring out whats "right" for aquarium systems very difficult.

Good point.

Jim

 

[TXnano]

Thanks to all that posted... you did give me questions that i didnt think of.
As far as keeping organisms that live 50 ft under the oceans surface, that is the reason we use antinic (maybe the wrong speeling) lights. Like I said in the first place i am new to this, and just like to know things. It seems to me that everyone wants to keep upgrading their lights all the time when i read posts, and just wandered if their was a breaking point to it all. I am an agronomist not a marine biologist. The research has been done for plants, but i can find nothing that far in detail for corals. Dont get me wrong... i love the idea of shoving a MH in a 5 gallon nano... that gets me thinking... but i just thought someone might share a thought or two today... and i enjoyed it. I hope i have more ideas to post in the future. ANd please if anyone else has something on the matter i would love to hear it.
PEace,
JAy

 

[Anonymous]

I did not relate Kelvin rating/color temperature to the wattage of bulb. At any rate, I am sure you are familiar with the fact that there is a large range among land plants's light requirement. For example, fern that lives under canopy of rainforest does not demand much when it comes to lighting. In fact, too much light can cause the demise of the plant. On the other extreme, many cacti do not grow much at all even under full sun light with very little cloud cover.

Same with coral and its algae. Many coral does not have very demanding light requirement. For example, some of the mushroom corals that I have grow and reproduce even when it is shaded heavily by rockwork. In the other extreme, some Acropora that I keep turns brown and lost its color when I switch to a bulb with lower output.

Overall, I want you to realize that it does not take much to keep the algae that live in coral to grow and reproduce, but in order for the coral to remain vivid and colorful, (this kind of ccntrodict my first reply about the high threshold of coral) it is necessary in most cases to have high output lighting. Of course there are many exception to this statement, since as I mentioned above, some coral are not very demanding when it comes to lighting.

The output of the sun of ~100W/ft^2 sounds about right. You can search for the answer by look up "PAR" and "einstein" as keywords. Keep in mind that it will take much more than a 100W bulb to give out same intensity as "100W' of sunlight, since the bulb is still not very efficient when it come to converting eectric energy to photo energy.

There are certainly many applicable lesson that common to both reef keeping and hydroponics, and in hydroponics, you have some people growing plants with florescent light, while some use HID bulbs. (MH is a type of HID bulb). Maybe you want to check out the idea in hydroponics and see what is their argument for using HID lighting :?

 

[TXnano]

Some comments... the light compensation point is pretty high for some coral. Furthermore, we don't want to use more efficient lighting (lower Kelvin bulb that give tank a yellowish look but with more PAR), so more electrcity is used than necessary.

David,
This sounded like you where relating kelvin to a bulbs intensity and efficient to me... but i didnt come here to argue. And as i found out from Jim's post... they havent found lighting that broke the threshhold for sps. And i know that a MH is an HID bulb. and you should maybe post things that help others.. not just cheapen their ideas.

 

[Anonymous]

This is "David Magen."

It is never my intention to cheapen anybody's idea, but if you feel this was the case, please accept my apology.

On the quote that you give above, I was trying to say that with same ballast wattage, a higher Kelvin bulb will give you lower intensity in the PAR region. Color temperature and wattage are two separate parameters of a bulb.