Is light over-rated in our reef

[duke62]

Ihave read some articles on reef keeping over the past few months which most contradict the others from feeding to skimming and to this topic of lighting.Some articles go into detail about over-rated equipment for our reef tank.I was more interested in SPS since this is the reef i have chosen to keep.But these articles go into every type of corals from softies to lps to sps.Some even go into inverts like the anemone.Now all of the articles talk about we need light but how much is the question. That was question was always raised.There was a experiment done where they had 2 separate tanks with the same light cycle.One ran PC lighting and the other ran MH lighting.The difference was they fed the pc lighting heavily and the MH they did no feeding at all.They had the same stocking in both tanks and different species of all corals.The pc tank over i believe it was 6 months had vey good growth with limited color up and the other tank had color but not much growth in fAct some pieces died off in the MH tank.So what is the real answer here.Are we given false facts about how much light we need.Does anyone really know the answers to what we as reef keepers are doing.One of the articles also wrote that 90% of the coralswe keep dont use photosynthesis as a food source they live on phytoplankton in the water.Now i know we cant recreate the food sourse in the oceans but what is the real answer here.Anyone care to share in your thoughts

 

[skene]

unfortunately I feel that 99% of all the crap we read is just statistical. Sure we cannot recreate a true ocean environment not because we can't, but because we cannot fully comprehend what corals truly need on a 24 hour basis.
sure we can say that SPS and LPS corals rely on calcium and alk so that they can grow. Sure we can figure that whatever water samples are collected can show us glimpses of what can be in the water column at any given time.. But also keep in mind that these corals grow naturally under different lighting... at different depths. There is no way possible that we can recreate its natural environment.
So then we have water qualities. Do we need to have high nutrients in the water? Do we need to strip the water in what we feel is too much crap.
It's been try and see if it works... and if it works 8/10... it has become "law".
and for that 2/10 maybe something different worked, but it was so awkward and unbelievable that it should never be tried.. cause it can't work... or it's whats believed to be.
it's been trial and error... and will continue to be.

 

[Imbarrie]

We know corals are light loving. In the ocean they all live within the shallow regions. The more shallow, the more variety and color life there is. There are deeper varieties that grow down to 120 and deeper but they are less photo dependent.
There is nutrient distribution at all levels but, by far, the most vibrant reefs I ever saw were in less than 20 feet of water. That is a lot of light. Something a PC could not replicate and MH can come closest to.

 

[prattreef]

It would be really helpful if you directly cited the articles you are referring to. The authors, their knowledge base, and POV are critical to evaluating the claims made. For instance, whichever article stated that the majority of corals kept in captivity don't need light needs to be conpletely disregarded.

To your main point though, I do believe we often over- light our systems. As a few examples, on my 8' 240g. system, I use 4 250w MH. and on Sanjay's 500g. he uses 4 400w MH. That is not a lot of light compared to many smaller systems using 250 and 400 w MH.

 

[duke62]

prattreef i didnt say they didnt need light it said they are not photosynthetic.ive been home for 8 months ive read tons of articles.i will try to remember which magazine i read it in.

 

[RARECLOWNSNJ]

I dont think corals are photosythetic like plants are.

 

[marrone]

There was a big thread on RC a while ago on how we under feed the anemones that we keep. The person, that started the thread, said that the amount of light we give them is way over board and that they would actually do better with less light, to almost no light, and heavy feeding.

 

[RARECLOWNSNJ]

Marrone,
Since you brought up anemones, now i can speak. Coral not so much.

Anemones can live off either, actually food or just light. When anemeones are fed they grow very quickly. With just light as food they grow but slower.

Anemones live off the algae in their tentacles. The zooxanethella is photosythetic and it provides the anemone with energy. Food to an anemone is a small chunk of algea or a small chunk of fish or anemonefish poop.

In some case anemones can catch whole fish and digest them. Not in our tanks because no one has a 2 foot magnifica or 2 gigantea or haddoni.

I dont agree with the over lighting. Some anemones like gigantea and haddoni can be found in less then 4 feet of water with sun beating on them. They grown like weeds.

 

[cowfish]

Marrone,
Since you brought up anemones, now i can speak. Coral not so much.

Anemones can live off either, actually food or just light. When anemeones are fed they grow very quickly. With just light as food they grow but slower.

Anemones live off the algae in their tentacles. The zooxanethella is photosythetic and it provides the anemone with energy.

I'm confused.

You state that anemones can live off just food OR just light. Then say that 'nems grow fast when fed, but grow more slowly with just light and later state that you don't think we overlight our tanks and nems live off of photosynthesis.

So, what are you trying to say? Can they live with little light if heavily fed, do they need both...?

 

[RARECLOWNSNJ]

Ok let me try to restate that. Sorry i was meandering.

1. Anemone can live off just light.\

2.Anemones can not live off just food long term, with low lighting or no lighting. They will not do well long term.

3. Anemones that have light and are fed grow quicker then ones ones with just light or just food.

4.Anemones dont live off of the proccess of photosythesis, they live off the photosythesis of the zooxanthella algae which creates energy.

 

[prattreef]

Let's clear things up here: The VAST majority of corals and anemones kept by hobbyists need light. How much, what spectrum, what duration etc. are all subjects of legitimate debate. Technically however, they are not photosynthetic because they don't perform photosynthesis themselves instead relying on the symbiotic relationship with the dinoflagellates ( Zooxanthellae) that live in their tissues to produce food from sunlight. So, to say corals are not photosynthetic while technically correct, is a gross misrepresentation of their need and dependancy on light.

All corals also feed on bacteria and plankton etc. but the ones that have developed symbiosis with Zoox cannot live long with out light.

As Barry notes above, the same is true for anemones.

Which brings me to my original point---you need to know the source of the information to determine whether it is credible or not. If someone wrote what Duke implied was written (i.e. most captive corals don't care about light) I would dismiss pretty much anything that author said out of hand as unreliable.

 

[RARECLOWNSNJ]

Thank you for the clear answer randy. So well written LOL

I think the OP took the non photosythetic thing to literally.

 

[KathyC]

Let's clear things up here: The VAST majority of corals and anemones kept by hobbyists need light. How much, what spectrum, what duration etc. are all subjects of legitimate debate. Technically however, they are not photosynthetic because they don't perform photosynthesis themselves instead relying on the symbiotic relationship with the dinoflagellates ( Zooxanthellae) that live in their tissues to produce food from sunlight. So, to say corals are not photosynthetic while technically correct, is a gross misrepresentation of their need and dependancy on light.

All corals also feed on bacteria and plankton etc. but the ones that have developed symbiosis with Zoox cannot live with out light.

As Barry notes above, the same is true for anemones.

Well stated Randy.

James (Duke62) back to your first post I think it is unfair to make the statement without mentioning what the specific corals were as it is too generalized and it is also somewhat misleading in reference to the title of your thread.

There was a experiment done where they had 2 separate tanks with the same light cycle.One ran PC lighting and the other ran MH lighting.The difference was they fed the pc lighting heavily and the MH they did no feeding at all.They had the same stocking in both tanks and different species of all corals.The pc tank over i believe it was 6 months had vey good growth with limited color up and the other tank had color but not much growth in fAct some pieces died off in the MH tank.

It isn't only about lighting, food plays a major role here depending on the type of coral.

 

[duke62]

well one of the things i read was yes most percentage of corals we keep are not photosynthetic but they need the light for the growth of the algae and zooplankton that they feed on.if they are feed a constant food source they will need little light to thrive.of course we cant give them a constant food sourse because we would foul our tanks.take us for example we dont need to sunlight to live but without sunlight we would not live as long.there was a study a few years back on people who work the night shift died earlier then people who worked 9 to 5 jobs.im sure corals get alot of what they require to thrive through the light just like how humans take in vitamins from the suns rays and kathy it didnt specifically mention which corals are the 10 percent that require photosynthesis as a main food source or i would have wrote that.my guess would to be gorgonias

 

[Imbarrie]

Should we define photosynthetic?

I believe corals act a lot like plants in that they harbor and encourage something that converts sunlight into a byproduct in which the host derives nourishment.
In plants that is through chlorophyll in corals it is through zooxanthellae algae. The only difference is see is chlorophyll acts like a biomolecule and the zooxanthellae is more like a symbiotic algae.

 

[KathyC]

well one of the things i read was yes most percentage of corals we keep are not photosynthetic but they need the light for the growth of the algae and zooplankton that they feed on.if they are feed a constant food source they will need little light to thrive.of course we cant give them a constant food sourse because we would foul our tanks.take us for example we dont need to sunlight to live but without sunlight we would not live as long.there was a study a few years back on people who work the night shift died earlier then people who worked 9 to 5 jobs.im sure corals get alot of what they require to thrive through the light just like how humans take in vitamins from the suns rays and kathy it didnt specifically mention which corals are the 10 percent that require photosynthesis as a main food source or i would have wrote that.my guess would to be gorgonias

But do we really only want to give them just enough light/or food to survive & not thrive?
Nor it is just about light & food, water parameters & flow would also have to be taken into account.

A link to the articles would be best
If there were a bunch of coral types people could grow with no light at all, don't you think we'd be seeing threads about it?

I'm also sure our corals don't need all of that Blue light people are blasting them with since the advent of LED's, but many of those tanks look great and the corals are clearly thriving.

I think many people tend to over-illuminate their tanks so they can keep a wider range of corals as they move forward in the hobby but ultimately they find their coral niche be it SPS, LPS or softies and fill a tank with those..whatever lighting happens to be on the top of the glass box.

Also...so we don't end up with a bunch of frightened night shift workers...they don't die earlier (!!) but they do have more accidents/illness/moodiness and stress then folks who work during the day...best not to mess with the Circadian Rhythm if you can avoid it!

 

[duke62]

the article does not say no light at all.it was referring to the amount of light needed.it states we use way to much light the illuminate our reefs.like i said it says we need the light just not as much as aquariest think.if you read everything i wrote all speciesof corals they tested which was softies lps and sps grew under pc illuminated light whiole fed dfferent types of phytoplankton while corals with just mh light had limited growth.there conclusion was the corals dont need intense light to grow and flourish but will get there vitamins and supplements from light they are not getting there nutritional values from the intense lighting.

 

[Quang]

my eyes hurt

 

[prattreef]

Again, who conducted these experiments, how well were they designed, how valid is the interpretation of results etc. needs to be provided to evaluate the conclusions. If you or I for example conducted the experiment, I'd chalk up the results as interesting anecdotal info and move on. If someone like say Sanjay or Chris Jury conducted the experiment, I'd take a much longer look at the results and seek out other people capable of evaluating the study for their opinions.

The point is, just because it is written up, doesn't mean it is valid--- and I'm not saying the study you cite isn't, I just have no way of trying to evaluate it.

This is a particular pet-peeve of mine regarding on-line forum discussions-- when people use screen names it is impossible to get a feel about who is citing what and from what level of "authority".

 

[duke62]

so what your saying is if a regular hobbyist did this experiment it wouldnt be valid because they dont have a naae like sanjay or chris jury?where did they get there reputation from?im not saying i agree with there findings i just want other people opinions on this.everyone gets a good reputaion from one thing or another.matter of fact i knowa member on MR wo is know for having extreme growth in a bigger tank and he used VHOs for years.his SPS grow like weeds and his problem crals are our dream corals.im sure everyone knows who im talking about.so im not ready to write this of as a farse article because i dont know who the author was but i do remember he was a marine biologist