? on CF vs LEDS

[kimba]

I had the 12 gal JBJ nano with CF and a few months ago replaced it with a new 12 gal JBJ with LEDs.

I'm wondering as far as coral placement with lighting requirements, how they differ. Are the LEDs stronger?

Any advice or suggestions would be great, thanks

 

[saltyfilmfolks]

Are the LEDs stronger?

Not always.

I wish everyone had a lux meter.($15 on amazon) It measures light intensity. it is a scientific method of doing so. and you could compare the two.

The other consideration is increased PAR.
2 lamps can have the same intensity, but one may have increased par.
In the case of LED as they can(not always IE Cheap) give a very concentrated "dose" of a specific frequency. that can be bad and one reason to acclimate, with a lux meter.

In the case of the JBJ, I know the spectrum pretty well, its more about intensity as their products so far IME, have been pretty generic in terms of High concentration of a singular frequency of light.(blue)
Its a bit "dumbed down" spectrum overall IMR IMO. But the intensity of my led lamps in the PRO JBJ hood was very high.

All that said, in your case, just use the normal acclimation methods. start on the bottom and move them up. Its likely the led you have may be brighter than the CF so hopefully youll be able to get some more higher light corals.
keep in mind, you may not have enough Par.

See if you can find the specs(false promises) from JBJ on the par or intensity. its hard to find ime.

 

[kimba]

Okay, I don't really know that much about lighting, I should read up on it ( I don't even know what par is ).

thanks

 

[saltyfilmfolks]

No sweat. we all start somewhere.
Dana Riddle. My Guru.
http://www.advancedaquarist.com/2002/2/aafeature
https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=dana riddle reef light

 

[kimba]

That was a good read. Thanks

 

[mcarroll]

A good reference (since we're all familiar) is sunlight.

• "Direct sun" at sea level is about 100,000 lux.
• 100,000 lux is about 2000 PAR.
• 2000 PAR is about 1000 watts/m2.

Just for an exmple with some very rough numbers: (bear with me on this!!)

• I measure a peak of around 40,000 lux over my tank. That's about 40% of 100,000 lux.
• My tank is 36"x18" on the surface. About .42 m2.
• By the math, replicating sunlight over my tank would take a theoretical (1000 w/m2 * .42 =) 400 watts or so.
• 40% of 400 watts = 160 watts.
• My Maxspect Razor is a 160 watt fixture.

Definitely get a [HASHTAG]#lux[/HASHTAG] [HASHTAG]#meter[/HASHTAG]

 

[kimba]

A good reference (since we're all familiar) is sunlight.

• "Direct sun" at sea level is about 100,000 lux.
• 100,000 lux is about 2000 PAR.
• 2000 PAR is about 1000 watts/m2.

Just for an exmple with some very rough numbers: (bear with me on this!!)

• I measure a peak of around 40,000 lux over my tank. That's about 40% of 100,000 lux.
• My tank is 36"x18" on the surface. About .42 m2.
• By the math, replicating sunlight over my tank would take a theoretical (1000 w/m2 * .42 =) 400 watts or so.
• 40% of 400 watts = 160 watts.
• My Maxspect Razor is a 160 watt fixture.

Definitely get a [HASHTAG]#lux[/HASHTAG] [HASHTAG]#meter[/HASHTAG]

This makes more sense to me and the little about light I know.

So I have another ?. When I had my old tank it had the day lights (10,000k with actinic combo) then I could turn those off and turn on a "moon light". Did this moon light give them any benificial light, or was it just for show? The reason I ask is my new hood with LEDs doesn't have a moon light.

 

[dacianb]

A good reference (since we're all familiar) is sunlight.

• "Direct sun" at sea level is about 100,000 lux.
• 100,000 lux is about 2000 PAR.
• 2000 PAR is about 1000 watts/m2.

Just for an exmple with some very rough numbers: (bear with me on this!!)

• I measure a peak of around 40,000 lux over my tank. That's about 40% of 100,000 lux.
• My tank is 36"x18" on the surface. About .42 m2.
• By the math, replicating sunlight over my tank would take a theoretical (1000 w/m2 * .42 =) 400 watts or so.
• 40% of 400 watts = 160 watts.
• My Maxspect Razor is a 160 watt fixture.

Definitely get a [HASHTAG]#lux[/HASHTAG] [HASHTAG]#meter[/HASHTAG]

Mcaroll,
In radiometry, radiant flux or radiant power is the radiant energy emitted, reflected, transmitted or received, per unit time, and spectral flux or spectral power is the radiant flux per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength. The SI unit of radiant flux is the watt (W), that is the joule per second (J/s) in SI base units, while that of spectral flux in frequency is the watt per hertz (W/Hz) and that of spectral flux in wavelength is the watt per metre (W/m)—commonly the watt per nanometre (W/nm).

When sun light is measured as 1000W/m2 is radiometric power of light and not electrical power. This radiometric power includes UV (full range), visible light, near IR and IR.
On the other hand a LED (even the most powerful frequencies as violet and deep blue) have a radiant efficiency of around 50%. So a deep blue led which consume 3W electrical power will have 1.5 W radiometric power (what you measure on sea level ). For whites, this radiometric efficiency is much lower.
On the other hand you have to subtract the UV and IRs from sun, as most of them are reflected, absorbed by sea surface - penetrating energy is much lower than that. But also your 160W fixture (electrical power) emit probably +/- 50W/m2 radiometric power.
If your lights are great for your tank, this is awesome, but I am not sure that your calculation method can be extended.

 

[mcarroll]

[...]I am not sure that your calculation method can be extended.

You just described in detail why I said the numbers were "very rough" vs accurate.



The math does work though, the numbers are close and it really is not a coincidence.

I think this is interesting.

 

[dacianb]

You just described in detail why I said the numbers were "very rough" vs accurate.



The math does work though, the numbers are close and it really is not a coincidence.

I think this is interesting.

Gods of science help us always

 

[hart24601]

To get even more confusing...


I would add that the daily amount of light (Daily light integral - DLI) is even more important than the instant intensity (PAR) IMO since we can adjust the photoperiod so easily in our systems.


From the below article:


"an aquarium coral receiving 500 µmol·m²·sec in a 12 hour photoperiod is receiving just about as much light as a shallow water (2" depth) coral does in Hawaii in February. If we bump the light intensity upwards to 525 µmol·m²·sec and the photoperiod remains at 12 hours, we would exceed the natural winter DLI."


http://www.advancedaquarist.com/2013/9/aafeature


This is pretty wild for a couple of reasons. That is a coral at only 2" depth!!!! That is as shallow as it gets. Plus with the heavy blue most LEDs run right in the peak photosynthetic spectrum the coral are receiving far more PUR than the daily light measured(see below for what PUR is) - http://blog.captive-aquatics.com/ca...r-and-reef-aquarium-lighting-what-is-pur.html


Not only that but PAR meters under report blue and severely under report violet and near UV leading most of us to think we have less PAR than we really do especially if using a good number of violet and UV diodes.

 

[kimba]

All this is hurting my brain. I try to understand it, but I jst don't. I feel more confused then before I asked the question. But I guess that's me, my corals are all doing great, so I'm gonna guess the lighting is enough.

But could I get a yes or No answer on the moon light question- do they provide any beneficial lighting for the corals?

Thanks

 

[saltyfilmfolks]

All this is hurting my brain. I try to understand it, but I jst don't. I feel more confused then before I asked the question. But I guess that's me, my corals are all doing great, so I'm gonna guess the lighting is enough.

But could I get a yes or No answer on the moon light question- do they provide any beneficial lighting for the corals?

Thanks

No
Unless they are of a great spectrum and of a high enough intensity. One way to know is do your corals respond to it an the other it get a lux meter.
Having the meter in your hand going outside and putting it next to a light bulb really does make it make sense.

And a par meter reports blue pretty well it's designed to do so.
It does not read uv at all in its calculation except what may accidentally affect the photo cell.

 

[mcarroll]

"an aquarium coral receiving 500 µmol·m²·sec in a 12 hour photoperiod is receiving just about as much light as a shallow water (2" depth) coral does in Hawaii in February. If we bump the light intensity upwards to 525 µmol·m²·sec and the photoperiod remains at 12 hours, we would exceed the natural winter DLI."

This seems to correspond with the "peak sun hours" graph I've posted around a few times...or at least the graph seems to illustrate the same idea...that light accumulates through the day in photo-sensitive systems (whether photosynthetic or photovoltaic):
From here: http://www.pveducation.org/pvcdrom/properties-of-sunlight/average-solar-radiation

This one might be slightly more clear:

It also makes the low-light thresholds for coral even more interesting to me.

(I'm generalizing across "all corals" so bear with me...)

• Survival down to 1000 lux (about 1% of surface levels).
• Growth between 5000 and 10000 lux.
• Seemingly, much above 50,000 lux and the coral has as many or more problems as benefits from the additional light.

Corals don't need a lot of light to survive and even prosper. And, in fact, it's pretty easy for us to over-do it.

The facts on UV and blue LED readings in our PAR and lux measurements (all those very-important colors are under-reported to varying extents) just mean that we can be pretty conservative with lighting

 

[mcarroll]

This radiometric power includes UV (full range), visible light, near IR and IR.

You still have me thinking on this...

If I'm remembering correctly, the 1000 w/m2 excludes everything that doesn't make it to sea level - so it's describing sunlight as we know it. (Right?)

Electricity is not the same "watts"...which is why we have elaborate electron-to-photon conversion systems on all our tanks!

Not perfect conversion systems, but 70% efficient or better in most cases...sometime 90% or better. Corals don't use all those wavelengths from sunlight anyway...or at least don't "need" many of them...some are even harmful. So I'm only going to be "so wrong" by assuming watts are watts in our case.

That's why the math works, IMO. It's really not just coincidence.

(It's a coincidence that the number is spot-on 1000 w/m2 in my case....I bet there's a pretty close range of w/m2 numbers for "most good stony coral tanks" if we could gather that data.)

 

[saltyfilmfolks]

It also makes the low-light thresholds for coral even more interesting to me.

if you happen to stand outside for years and years and watch smell and listen as the sun comes up and goes down it makes sense. If you happen to have a light meter in your hand, like me, its weird. theres a massive correlation.
you can smell trees at dawn, when theres still little to no light.(no matter how you measure it)
these simple observations are often missed by engineers. and is somethin I consider when chosing a light cycle.
remember, the sun is sending more particles than just light. us monkeys dont survive on light. the ones that do know its coming.
so even if I have little no no light ( to 100 lux fc watever) o a ramp, It starts near dawn. and ends near dusk. Circadian rythym, based on more than just visible light.

I would wager that by, with computer modeling light and temperature scenarios in a reef tank, we will(and are) going to breed more and more corals, and likely fish too.

silly monkeys.

 

[saltyfilmfolks]

You still have me thinking on this...

If I'm remembering correctly, the 1000 w/m2 excludes everything that doesn't make it to sea level - so it's describing sunlight as we know it. (Right?)

Electricity is not the same "watts"...which is why we have elaborate electron-to-photon conversion systems on all our tanks!

Not perfect conversion systems, but 70% efficient or better in most cases...sometime 90% or better. Corals don't use all those wavelengths from sunlight anyway...or at least don't "need" many of them...some are even harmful. So I'm only going to be "so wrong" by assuming watts are watts in our case.

That's why the math works, IMO. It's really not just coincidence.

(It's a coincidence that the number is spot-on 1000 w/m2 in my case....I bet there's a pretty close range of w/m2 numbers for "most good stony coral tanks" if we could gather that data.)

and 90% of reefers still only need a lux meter.

 

[mcarroll]

silly monkeys

dance, monkeys! dance!

 

[saltyfilmfolks]

dance, monkeys! dance!

if you follow the forum, they do. I do too.

 

[chefjpaul]

Great thread here.
Just ordered a new lux meter.