The truth about lighting

[Scooterman]

RC has PAR ratings post somewhere, I'll look for it, it was based on 250w mh bulbs though.

[mojoreef]

Hey I better not get any care packages on my door step now . Boomer I have not read nor was I refering to any post by you. I was just tryng to point out that Bulb K ratings do make a difference, so I plead innocence .
Folks go to our library and look under the lighting section. thier should be a few articles by Sanjay. His articles are on testing that he has done a large varity of bulbs in the reef hobby. they should have all the par ratings and wave length graphs available. this will probibly answer a few questions so far. Take a peek at them and then lets get a bit deeper.


Mike

[Cougra]

Blue light as compared to Reds, there is a frequency difference that makes them so different, Thinking out loud here but red lights are at higher frequencies thus fading much quicker, kinda like microwaves, the frequency is so high that you could point the megaton or klystron oscillator a foot away and get no ill effect! Thoughts out loud here, sorry.

Just to clarify:
Blue light has a shorter wavelength but higher frequency then red light

The shorter wavelength allows the blue light to move between water molecules more before hitting an obstical (water molecules) there by penetrating deeper in the oceans.

Red light has a longer wavelength but lower frequency.

[RogueCorps]

Originally posted by Boomer
Calfo made an interesting point. He believes that light supplies only up to 15% of the nutritional.

This is nonsense. Calfo seems to have missed the bazillion studies that say otherwise, often reported as P-R or CZAR. Some corals can get as high as the high 90's % of their needs just on light. And if corals and anemones did not mucate they could get over 100 % of their needs from light.

I think the quote is just missing the intent of his statement. Calfo's discussion was about using invertabrate reproduction strategically for benefit in specific systems. For instance, using specific sized mediums for promoting amphipod or copepod populations depending on the feeding polyp sizes of the corals that you keep.

Part of the point that he was making, that I've also heard from others, is the fact that corals have the greatest body percentage devoted to food capture of all animals, and that deficiencies in light can be replaced by food. Basically a coral covered with polyps is lots of tentacles and mouths, meant to capture food and eat. It just makes sense based on their body structure.

He noted this in contrast to the nutrient starved tanks of the 80s, and also to hobbyists who are over-obsessively dependant on light... running tons of 400 watters... even 1000 watters... He noted one hobbyist who is experiencing good growth and colors under 175mh. There is also "brooklynjohnny" on nano-reef.com who's got acros and clams in a nano tank under PCs I believe. The difference noted in these systems is feeding.

-Rogue

[LaquitaWilliams]

one thing about actinics....many say they are only for aesthetics as was stated earlier....

i'm sure i'm not the only one to notice that my soft corals (zo's, shrooms, star polyps) stay open with only the actinic on....however, maybe they're not getting any nutritional benefit from the actinic but they're open, ya know?

don't know a lot about lps or sps with reagrds to actinic, but i can say i sure love the actinic color it produces!
another thing is my mandarins only spawn during the late actinic cycle....now maybe that's related to their own bio-rhythms knowing the tanks photoperiod, maybe not....but i'll keep my actinics!!

[mojoreef]

Part of the point that he was making, that I've also heard from others, is the fact that corals have the greatest body percentage devoted to food capture of all animals, and that deficiencies in light can be replaced by food. Basically a coral covered with polyps is lots of tentacles and mouths, meant to capture food and eat. It just makes sense based on their body structure

RC thats not really right at all. it has to do with thier body structure, but he is missing a few big points. Take sps for example, lots of mouths and polyp tentacles, but they are not designed properly for the capture of prey. SPS nemacyst (which are what most corals use to capture prey) have no barbs, thus they are ineffective, you add that to the ammount of energy required to fire off these namacysts and that source of food capture does not get used. To off set this the SS type coral has a highly evolved electron transfer sytem, to transfer light photons to reaction centers where it is converted to atp and others, from thier its food, thus up to 98 % of its food source is light. Saying that any coral only gets 15% of its food from light he must be talking about some type of cave dweeling corals. Saying that if they dont get it from here they will get it via a different way is a bit misleading. they can compensate a bit, but they live in the areas they live in for a reason and have spent thousands of years evolving to take advantage of each of thier particular enviroments.

MIke

[mojoreef]

LaquitaWilliams I dont think that atenics are just for looks. I have seen them grow to many corals to agree with that statement made by dana. You can not look at a coral polyps opening or closing for any signs of good or bad. the polyp of a coral is used in to many different thing. Its used for offence/defence/reproduction/food gathering/light gather/sensoring and so on.

Mike

[RogueCorps]

Hey Mo!

Well, I've heard similar info from Toonen as well (you're other good pal) that corals are built to feed. He made another point that most polyp extension is at night, and is recessed during the day. Doesn't it make more sense that if an animal were trying to maximize it's surface area for photosynthesis that it would extend under sunlight and not receed? Hmm...

-Rogue

[EdgeKrusher]

I wasn't saying to get rid of your Actinics at all. I like how they make a tank look. I'm just saying that what I read stated that they don't serve much of a purpose other than asthetics. Now I haven't read anything scientific about the effects of Actinics on corals so there's no telling how much truth there is to that statement. Hopefully when Dana complete's more of his experiments they will clarify alot of things.

Peace

EK

[mojoreef]

HIya RC, nope not at all my friend. Corals extend thier polyps at night for a variety of reason. the main one is that most preditors are asleep and thus wont eat thier polyps. Polyps are not the only place a coral has zoox, the zoox is all over the corals. Hmmmm back..hehehe

Edge I was refering to Danas statement. I do believe that actenics do provide lighting that a coral can use, just not alot of it.



Mike

[mps9506]

Originally posted by ScottT1980
So, at least to this point in the discussion, it is fair to say that in fact, kelvin DOES matter, perhaps not directly (although I still have some reading to do here, just way too busy), but it still can affect the PAR value. Is this a correct assumption?

This goes against what I have percieved to be the general consensus in the hobby. I always assumed a 110W bulb or a 400W MH bulb is going to have the same PAR/intensity regardless of kelvin. So true, while kelvin rating does have it aesthetic value, it also does have an intensity value that should be considered. Am I correct here? I am just drawing this conclusion from quick skimming of the actual data (without looking at much discussion, plus that RC thread is going to take me a good two hours to mull over).

TG, I agree and really was shocked to read that.

Take er easy
Scott T.

Scott,
One thing you may want to take a look at or think about with the Kelvin and Par comparisions. Take a look at JB's tests of 250watt bulbs. Par is going to have variations between bulbs not because of the Kelvin, but just between all bulbs, probably between identical bulbs also. There is a general correlation between high Kelvin bulbs having lower par. ie, generally a 250 watt 20k bulb has less par than a 250 watt 10k.
Just remember though that the Kelvin and PAR are distinct things.
When it comes down to it, PAR is what provides your corals the energy to grow. Kelvin in general changes the way your corals appear.
There is a good paper somewhere, I believe by Sanjay Joshi that describes the drawbacks of using PAR as a measurment to determine what grows corals best. I'll try to find that when I get the time.

RC,
I don't believe that the zooxanthellae are contained within the tenticle section of the polyps, but withing vacuoles within the tissue cells of the gastrodermis.

[RogueCorps]

Oh, I wasn't "hmm-ing" as in "in your face" Hmmm... I am really "hmm...?" for things that I'm trying to understand here.

Wait a sec... So if they can't effectively catch food then why extend at night at all? I'll admit I haven't read everything, but am wondering why many biologists are saying to feed your corals if you're saying that they hardly eat. I think finicky acros growing as well as staying well colored under a 175mh is evidence that food is an important part of the formula. I think it was David Cripe of Monterey who said that growth structure had little to do with "reaching" towards light, and has much more to do with flow.

Just learnin' here...

-Rogue

[EdgeKrusher]

Mike,
I was replying to LaquitaWilliams's reply. LOL
I belive that corals do use some of the light produced by Actinics, since they tend to use blue/violet litght for photosynthisis. I want to learn this as best as possible, so correct me if I'm wrong.

EK

[ScottT1980]

LOL...this is really the sort of disccusion I was looking for, keep it coming. Mike (MPS), yeah, I totally agree with you and definitly see some variation. In fact, I was going to try to throw it in an excel spreadsheet or even better, in SAS to try to get some statistical analysis of the data to see the correlation between PAR and kelvin. I certainly realize that they are two different entities measuring two different things. Nevertheless, just visually looking at the data, it certainly appears that there is a bit of a correlation, especially between the 6500K and the 20000K.

[Scooterman]

Originally posted by Cougra
Just to clarify:
Blue light has a shorter wavelength but higher frequency then red light

The shorter wavelength allows the blue light to move between water molecules more before hitting an obstical (water molecules) there by penetrating deeper in the oceans.

Red light has a longer wavelength but lower frequency.

Thanks, I would of had to remove the dust off a few books to remember myself that, Man if I want to play I better be sure what I thinking LOL! Now How can this be translated or related in relation to PAR ratings?