PAR help please Dana Riddle

[Reesj]

As a guy with custom tank setup I had to setup my light inside the custom hood that came which hangs just 2-3 inches above water level.
I'm sure most people would also like to know some general PAR numbers for corrosponding Lux levels.
So @Dana Riddle
For a Light 2 inches off water,
with water level illumination level at 10000Lux/15000Lux with 50/50 white to royal blue ratio(Most common ratio. if not 66.6 blue to 33.3 white also might help) What will be the PAR value, 6/12/18 inches below water.

Can you please let us know? I'm sure this will help a lot with custom light to figure out their PAR values. Thanks a load

 

[Dana Riddle]

As a guy with custom tank setup I had to setup my light inside the custom hood that came which hangs just 2-3 inches above water level.
I'm sure most people would also like to know some general PAR numbers for corrosponding Lux levels.
So @Dana Riddle
For a Light 2 inches off water,
with water level illumination level at 10000Lux/15000Lux with 50/50 white to royal blue ratio(Most common ratio. if not 66.6 blue to 33.3 white also might help) What will be the PAR value, 6/12/18 inches below water.

Can you please let us know? I'm sure this will help a lot with custom light to figure out their PAR values. Thanks a load

Let me make sure I understand - Light intensity is 10,000 - 15,000 lux? I've got some business to attend to this morning. I'll look at this when I get home.

 

[oreo54]

Meanwhile.. you can play w/ this calculator...

Convert Lux to PPFD - Online Calculator | Waveform Lighting

Online calculator to convert illuminance (lux) to PPFD (micromoles per second per meter squared).

www.waveformlighting.com

red plus blue plus white is probably the closest..

 

[Reesj]

10000 and 15000 lux. PAR at 6 inches, 12 inches and 18 inches below water level. Will be a great help if can.

 

[oreo54]

since LUX is area/height dependent you need to measure LUX at 6, 12,and 18" to start..
Where are you getting the 10000 and 15000 measurements from?

By chance are you referring to lumens? (Just checking)

Hang the light and measure it in air if need be ..at your estimated heights.. light "face" to tank depth.

Conversions of LUX to "PAR" (PPFD) range from 1LUX = .12PPFD (PAR in common usage) for pure blue LED
LUX/8.6

to 1 LUX = .02 PPFD for natural daylight..
LUX/43.5

 

[Reesj]

since LUX is area/height dependent you need to measure LUX at 6, 12,and 18" to start..
Where are you getting the 10000 and 15000 measurements from?

By chance are you referring to lumens? (Just checking)

Hang the light and measure it in air if need be ..at your estimated heights.. light "face" to tank depth.

Conversions of LUX to "PAR" (PPFD) range from 1LUX = .12PPFD (PAR in common usage) for pure blue LED
LUX/8.6

to 1 LUX = .02 PPFD for natural daylight..
LUX/43.5

No I mean Lux level . Lumen is the emitting source brightness. You do not measure a points illumination level by lumen in general practise. Beleive me I'm an electrical Engineerign lecturer I teach these stuff.

You Lux to par numbers are wrong in quite a lot of area.
You can not convert it unless done roguhly as dirrent LED colours emite diffrent amounts of PAR values for diffrent Lumen levels. Not to mention the distortion happening inside sea water. (Inverse square law directly does not correlate from air to sea water)

 

[oreo54]

You need to measure LUX at the point of interest..
my LUX and PPFD (PAR is NOT the correct term here) are guesstimates based on mine and others experience..no more no less.

going back to lumens (which is the spectrum sub set of PPF (PAR)) and what is used to calculate LUX based on Lumens per area..and the curves the sensor should be calibrated for, yea makes it a wee bit difficult but I stand by my statements.

People have taken the time to measure both LUX and PPFD to come up w/ those figures..

It's not pulled from ones as btw..

One lux is equal to one lumen per square metre:
1 lx = 1 lm/m2 = 1 cd·sr/m2.

But I get part of your point saying 10000 LUX just means you estimated 10000Lumens per sq meter..
Now where does that get you in relation to height?
It's meaningless..

Problem w/ lumens (LUX) to start with:

And why conversion factors VARY so much..

Whether you add a filter to a white light or use a dedicated blue light, you will end up with light output primarily in the 450 – 460 nm range, solidly in the blue. In this range one watt produces only about 34 lumens. That’s right – only about 5% of the lumens of green light! It’s still 1 watt (radiometric), but only 34 lumens (photometric).

Lumens and Lights for Fluorescence - NIGHTSEA

This article discusses the relationship between lumens and lights for fluorescence, to get a better understanding of light ratings.

www.nightsea.com

seawater.. freshwater.. inside glass only distort delivery ..which is why you need to measure LUX in the tank at least ..free air ..useable.. under water best AT the point you want to estimate at..


100000LUX 2000PPFD roughly the measurements of the sun at sea level..
0.02... conversion factor or LUX/50..

sort of back to your orig question IF you measure 10000LUX at the water surface and now want to know what "PAR" is at at 6" that really doesn't work too well ..
One point doesn't give a good estimate based on all the factors you know about..
Give me 2 points..

Inv sq law doesn't apply, we know that.. what does?
How would you ESTIMATE it at 6"?

Say your light source exit was 4" off the water line and 10000LUX one could .. very roughly.. figure at 8" 1/2 of the LUX.. say 5000 LUX (Old discussion )
Based on a guessed conversion figure (50/50 blue white isn't known to me..)

128PPFD... starting w/ 257 PPFD initially

an estimate I wouldn't be real comfortable with due to the initial measurement too close to a broad light source..

 

[Reesj]

I don't think you seems to understand what I'm asking or whast is goign on .
PPFD is usless as no one ueses that. All the sites and information reguarding corals placements are normally instructed in PAR values.
Also the Hight is important to know, how much PAR value you get at those levels directly below water surface. I seriously fail to undestand what point your trying to make or your confucsion with LUX and Lumens even after I explained what each one does. Lumens or candela is usless as we are not even taking mean hemispherical Candal power as LED have even lower range than 180 degrees.
You measure the value at 6 inchs using a PAR meter. The reason I asked Dana; casue I know he has the items to test with lights, Lux meter and a PAR meter .

 

[Reesj]

Also if we can have a guidlinefor data with certain Blue to white ratio for known lux level at water surface we do not need to rely on inferior sites to give us false conversion data.

 

[oreo54]

PAR is the INCORRECT common usage of PPFD which is what quantum meters measure ..
It's you that doesn't quite get it..sorry..

About PAR, PPF, And PPFD

If you're shopping for horticulture grow lights, you may have seen the terms watts, lumens, LUX, foot candles, PAR, PPF, PPFD, and photon efficiency.

fluence.science

PAR (photosynthetically active radiation) is area-less and not relevant..
PPFD is equiv (in meaning not numbers) to LUX .. People INCORRECTLY use PAR..

PPFD
PPFD is photosynthetic photon flux density. PPFD measures the amount of PAR that actually arrives at the plant, or as a scientist might say: “the number of photosynthetically active photons that fall on a given surface each second”. PPFD is a ‘spot’ measurement of a specific location on your plant canopy, and it is measured in micromoles per square meter per second (μmol/m2/s).

 

[Reesj]

PAR is the INCORRECT common usage of PPFD which is what quantum meters measure ..
It's you that doesn't quite get it..sorry..

Dude can you please stop derailing this thread.
You clearly seem ignorant or does not seems to read the replies. You are trying to talk about something completely out of topic and something I have no intrest in or what was asked in topic.
You can give it in whats ever unit thats you think is correct and I do not care what your openion is on right or wrong term. I did not ask you about the right terms to measure light. Please reply releavent to the topic and soem stuff completely irelavent and usless. I have no intrest to know valuesin PPFD and i have clearly given the reason.
Please maek some education programs for peopel in industry to put their values and all the sites to put their values and to sell meters not to value PAr but PPFD. This is not the place.

 

[oreo54]

All those "PAR" measurements you read about are NOT "PAR" but PPFD.
any measurement using an Apogee, Li-Cor or Seneye..

It's a fact, not an opinion.

 

[Reesj]

All those "PAR" measurements you read about are NOT "PAR" but PPFD.
any measurement using an Apogee, Li-Cor or Seneye..

It's a fact, not an opinion.

Man you are annoying and trying to derail this thread.
I have a Masters in Electrical and Electronic engineer from University of Nottingham and at SLIATE I work as a Lecturer. I teach about illumination Engineering. I do not want your internet found lessons to talk about PAR or LUMENS or LUX which you seem clueless about.
@ oreo5457 If you have PAR meter and LUX meter and can do the experiment I asked, Post the results. If not please keep quite and stop derail this thread. I do not care about your internet lessons.

 

[oreo54]

I do have a PPFD meter (Seneye) and a LUX one..
Sorry no blue/white LED lights..

gee w/ your education I'd think you could answer your own question...

I answered your poorly thought out question best I could..
There are plenty of others here that did LUX/PAR(ick) comparisons w/ black box lights..

Maybe do a search eh..

The Modified Black Box Thread

So, over the past year I've been changing LEDs and lenses to find a good spectrum, light dispersment, limited shimmer and most importantly less "disco" effect, on my 165w wifi black box. I think I've found a combination. I decided to keep the 120° lenses and mixed 90° beaded and not beaded...

www.reef2reef.com

I just dropped my surface lux from 42,000 to 37,000. In the past couple days, one of my acros was beginning to lose color. I decided to put my lux meter in a plastic bag. (Poor mans submersible meter ) Anyway, you know, it's a round about number to begin with. But, this acro was getting about 27,000 lux or 455 PAR with a 60 conversion. A par of 350 is what I was wanting to begin with so, it's now at 21,000 lux for this coral.

I adjusted my modified box to 32% white and 63% blue. Crossing fingers this is the sweet spot.

 

[Reesj]

I did read that as well as Qutie a few and almost nothing adress what I'm asking. Not many seems to be using hood lights 2-3 inches off water level or for values I said. Thast why I asked some one who can answer.
If you have the correct answers give those, if not let some one who has do it answer.
With my education or with any ones, you can't know the values a PAR meter gives out wihout having one. You can make guess like 50:1 or 40:1 but those are guess not right answers.

 

[oreo54]

Then go buy one...should be affordable for you..
Problem solved..

again, and admittedly JUST to be annoying.. Those aren't PAR meters..
Use actinic/daylight conversion factor..I said approx 50...from the calc.. This used 38
200 vs 263..how close do you want to guess?
Lux to PAR Conversion Fhttp://www.reefcentral.com/forums/showthread.php?t=1971094actors

Light Source	Constant
Sunlight	54
Warm White Fluorescent	76
Cool White Fluorescent	74
URI (now UV) Actinic Fluorescent	18
URI (now UV) Daylight Fluorescent	54
Actinic/Daylight Combination	38
Philips 03 Actinic Fluorescent	40
Panasonic 6,700°K Power Compact	72
Panasonic 7,100°K / 6,700°K Combination	55
Osram Powerstar Metal Halide	57
Ushio 10,000°K Metal Halide	54
Coralife 10,000°K Metal Halide	30
Venture "Daylight" Metal Halide	46
Radium "Blue" Metal Halide	51
Fusion Sulfur Lamp	41
Westron Mercury Vapor Lamp	70
Iwasaki 6,500°K Metal Halide	57

 

[oreo54]

..it is possible to convert lux measurements to PAR values. Use these results with some caution - in most cases it would be safe to assume the results will be low.
•Divide blue (450nm) LED Lux by 69
•Divide white (7,300 K) LED Lux by 45
•Divide blue (450nm)/white (7,300 K) combination LED (2:1 white/blue ratio) Lux by 67

Using a LUX Meter for PAR readings. How to calculate PARS estimates? - Reef Central Online Community

Using a LUX Meter for PAR readings. How to calculate PARS estimates? Lighting, Filtration & Other Equipment

www.reefcentral.com

Here is a nice article that shows some typical tank PAR values and differences between light setups.

http://www.advancedaquarist.com/2003/8/aafeature

So I measured my tank Lux values (under water) with my Meter.
I was getting Lux values of 10,000 at the top, 5,000 at the bottom, and around 8,000 in the middle areas.
So this would roughly convert my 2x 250W 14,000K Giesemann "Megachrome Coral" bulb setup "using 50 a conversion" to 200 PAR, 100 PAR, and 160 PAR.
Rough guess, but better than nothing.

Corals know best.

since you want Dana's .advice.. orig link below.
BTW. He already knows how I feel about the "PAR" thing..
Ranks up there w/ the genus..species thing..
genus, specific epitaph and the SPECIES is a binomial of those 2...
species:
‎Acropia cervicornis
genus Acropia.. spec. epith cervicornus

Aquarium Equipment: PAR Meters and LEDs - How Accurate are the Measurements? A Comparison of Three Meters and Lux to PAR Conversion Factors for LEDs

How do PAR meters stack up to one another? Dana delves into the data comparing and contrasting three light meters and gives us his take on the results.

www.advancedaquarist.com

BB LED whites can vary from 6500k on up.. for 50/50 boxes.. mostly higher like 10000K throwing off the blue/other ratio.Thus the "guesstimate"
Dana uses 67 per the above..

Lux readings

I am going to try increasing the intensity slowly. The controller only goes in 5% increments so I'll bump it up by 5% every week or two. With the way it mounts to the biocube (not that well) and the gooseneck being fairly difficult to manipulate I'll leave it as it is physically for now and...

www.reef2reef.com

 

[oreo54]

Again.. for $200 you can get a Seneye and get the "correct" answer yourself.

Then you don't need to bother people w/ your little err "problem" and I don't have to bother you..
Your question is 2 parts
1)LUX to PPFD conversion which I addressed as best as I can considering each light spectrum will be slightly different

2)Given one data point (say 10000 LUX @ 2" ) calculate PPFD at the other depths..

Your initial PPFD is approx 200.. (covered in great detail above)
Using Dana's conversion factor of 67..149 PPFD w/ 10,000 223 @ 15000 LUX

Adding 6" of depth it will be considerably less than 200PAR..maybe.
Starting w/ a measurement soo close to the source makes guesstimating tricky because the farther down the farther diodes start to increase their influence on the spot measurement..for awhile

So at 18" from the surface starting w/ 149 PPFD to use a scientific term your "PAR" is.......... didly squat...

That said, I also don't trust your LUX measurement so close to the light fixture to be representative of the true LUX available..simple geometry thing..@ 3" 90 degre lensed diodes produce about a 6" diameter cone of light so diodes over 6" away from the LUX sensor contribute les to the reading than may be represented in the overall photons available in reality.
I've measured LUX w/ LED COB's and at close distances things get wonky (more scientific terms) though that was more in the 2" range for a single 20W COB.
Like I said, your initial question looks flawed..

Lets' look at a fw example since 200 "PAR" at the surface is "didly squat" for a reef tank I need to revert to fw:

So to directly answer your question
at 6", not much 12" squat, 18" didly squat

all humor aside, again I thinh your initial LUX measurement parameter is flawed..
Best to start w/ measuring LUX in free air (if need be) at 6" and prob another measurement..

Hey if someone knows better I'm all ears.

Maybe the fact that nobody else addressed your problem is a "hint"..

 

[Reesj]

My lux meter should be accurate and I can't risk puting it inside water. The Lights are custom made and those are just refrense points . Also its not a point ligth source but a distributed strip with backup custom set.
I don't care about explaining my system and if you want a basic look check the build tread. Diffrent LED colours provide diffrent PAR values same LUX value. Hence reason I asked for a 1:1 or 2:1 conversion factor.

$200 is not nothing specially when you earn in Sri Lanka.( Specially considering I have no further use for it).

Also @Dana Riddle was going to help before you decided to derail the tread and sending anyway any and everyone.

 

[scardall]

My lux meter should be accurate and I can't risk puting it inside water. The Lights are custom made and those are just refrense points . Also its not a point ligth source but a distributed strip with backup custom set.
I don't care about explaining my system and if you want a basic look check the build tread. Diffrent LED colours provide diffrent PAR values same LUX value. Hence reason I asked for a 1:1 or 2:1 conversion factor.

$200 is not nothing specially when you earn in Sri Lanka.( Specially considering I have no further use for it).

Also @Dana Riddle was going to help before you decided to derail the tread and sending anyway any and everyone.

Then solve your issue and buy a "apogee Par meter. Only $300+ depending on condition and model . PS: Chill dude