Conversion lux

[Wolf94]

hello

I don't have a par-meter, just a lux meter.

I wanted to get an idea of the par value on my viparspectra 165w lamps on the water surface.
just a rough indication of this value.

I have about 22,000 lux on the surface of the water.

we can divide rather by 45 or rather by 60 approximately? I do not remember.

it's just to have an approximate value, so as not to burn corals

thank you

 

[dstockwell]

What size tank and what numbers are you running on blue and white.

 

[Steven Garland]

I kinda wanna know the samw,I have the Photon app on my phone and kinda what to to know what to make of it all lol.

 

[oreo54]

Common in the past was divide by 70.
About the same factor with low cri daylight LEDs.
22000lux is 300 par


Pure 450 nm light divide by 8.7
22000lux is 2542 par

https://www.waveformlighting.com/horticulture/convert-lux-to-ppfd-online-calculator.

Sooo the factor will depend on the blue to other ratio. But red has the same issue as blue.

Luxmeters: thoughts, findings, comparison

Going into details here :bigsmile: This post may look a bit technical for some but fear not, it mostly contains things that I picked up about the subject over the last couple of weeks, I am not at all a physicist specialising in optics (I am a biologist). Disclaimer: having said that, I feel...

budgetlightforum.com

 

[Steven Garland]

Wow so my par really is pretty low,8" away from my leds my lux is 2300 with both t5 bulbs and leds and just leds its 2200 lol oh man.. thats roughly 252 par at my water surface 8" from the leds

Seems low with 2 Lux M's (600mah),2 SemiLed Ultramarine Blue (440-445nm @700mah) and 7 violets from 385-430nm (600mah)

 

[oreo54]

8" is pretty far for lensless leds.
28" spot size..

 

[Steven Garland]

8" is pretty far for lensless leds.
28" spot size..

I mean I guess I could get some lenses and swap the M's out for Rebel ES royals.

 

[Wolf94]

Bonjour.

viparspectra 165w

22.000 lux --> 20cm water line


ALL Lens OFF
100% blue 25% White

If 300 par water line roughly, so you think i must put more whites ?
To 40-50 % ?
Or more ?

My tank is 20" depth

 

[Wolf94]

Le commun dans le passé était de diviser par 70.
À peu près le même facteur avec des LED lumière du jour à faible cri.
22000lux est 300 par


Lumière pure à 450 nm divisée par 8,7
22000lux est 2542 par

https://www.waveformlighting.com/horticulture/convert-lux-to-ppfd-online-calculator .

Donc, le facteur dépendra du rapport entre le bleu et l'autre. Mais le rouge a le même problème que le bleu.

Luxmeters: thoughts, findings, comparison

Going into details here :bigsmile: This post may look a bit technical for some but fear not, it mostly contains things that I picked up about the subject over the last couple of weeks, I am not at all a physicist specialising in optics (I am a biologist). Disclaimer: having said that, I feel...

budgetlightforum.com

/70 ?

very hight

 

[Wolf94]

Êtes-vous tous d'accord avec le /70 ?

Not less roughty ?

 

[oreo54]

Lux to PAR Conversion Factors​

If you have a lux meter, 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

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.

web.archive.org

I think it will be really low @ 67
Need NEW data really.

Product Review: Lighting for Reef Aquaria: Tips on Taking Light Measurements

Hobbyists using a light-measuring device for the first time will probably be surprised at how rapidly the light field can change within an aquarium.

web.archive.org

"Actinic/daylight @ 38 may be closer...
O/ps 22000 lux = 579 ppfd.

ONE measurement:

When I tested the Visparspectra 165W in a 24” cube, hung @ 14” from the surface, 100% blue, 1% white, I got average PAR readings at 650 at the water. Even at 80, was getting easy 450.

 

[Wolf94]

Hello.

Im 100 blues and now 30 whites but ALL LENSES OFF.

20CM water line.

What New data do you need Oreo ?

Cordially

 

[dstockwell]

I have two viparspectra 165 10 inches above the water, on a 55 gallon running 25 blue 2 white par at surface is 300.

 

[oreo54]

Hello.

Im 100 blues and now 30 whites but ALL LENSES OFF.

20CM water line.

What New data do you need Oreo ?

Cordially

People who actually measured both par and lux using a "black box" like configuration.
Above us is a thread stating:

two viparspectra 165 10 inches above the water, on a 55 gallon running 25 blue 2 white par at surface is 300.

So if using "my guess" as to a conversion factor of 38 their lux reading should be around 11400..
Enough of measurements like that and "we" can get some idea of the guesstimate

I would not trust using a Seneye for this . Personally their lux measurements are sketchy.
They are 2x lower than should be if the lux meter I own (INS DX-200) is accurate.
That one is cosine corrected where the seneye is not. Actually makes close par readings w/ the seneye a bit less accurate too.

Above chart shows conversion factors from 76 to 18..

60-70 seems more daylight orientated so if one runs all white should work
Theoretically one could work up a table for
1:1 blue/white use 55
2:1 blue/white use 45
4:1 blue/ white (100%/25%, 75/18 ect) use 40
10:1 blue/white ( 100%/10% ect.) use 30


Lenses off or on doesn't matter for "your" readings really. In that I mean "it is what it is" with your configuration. Just need to get a handle on the conversion. Of course it does matter as you get deeper in the tank but that is a totally different problem

Like 300 surface par with lights with 120 or 90 degree lenses may (should) have different measurements 10" under water due to concentrating the photons with the smaller lenses.

Not sure it is worth that much effort though. Some numbers really are close percentage wise..
20000Lux/ 55 = 363.6 PAR
20000 Lux/ 50 =400 par 9% more
20000Lux/ 40 = 500 par 28% more

So back to reality.. personally for your 22,000 LUX I'd "err on the high side" BUT you would need to add what % (or really what ratio) of blue to white you measured.

I was temped to suggest the Actinic/Daylight number at 38 but 45 may be better. Again depends on your percent blue to white.

479 par using 45 bringing us full circle to your orig post.....

 

[Wolf94]

People who actually measured both par and lux using a "black box" like configuration.
Above us is a thread stating:


So if using "my guess" as to a conversion factor of 38 their lux reading should be around 11400..
Enough of measurements like that and "we" can get some idea of the guesstimate

I would not trust using a Seneye for this . Personally their lux measurements are sketchy.
They are 2x lower than should be if the lux meter I own (INS DX-200) is accurate.
That one is cosine corrected where the seneye is not. Actually makes close par readings w/ the seneye a bit less accurate too.

Above chart shows conversion factors from 76 to 18..

60-70 seems more daylight orientated so if one runs all white should work
Theoretically one could work up a table for
1:1 blue/white use 55
2:1 blue/white use 45
4:1 blue/ white (100%/25%, 75/18 ect) use 40
10:1 blue/white ( 100%/10% ect.) use 30


Lenses off or on doesn't matter for "your" readings really. In that I mean "it is what it is" with your configuration. Just need to get a handle on the conversion. Of course it does matter as you get deeper in the tank but that is a totally different problem

Like 300 surface par with lights with 120 or 90 degree lenses may (should) have different measurements 10" under water due to concentrating the photons with the smaller lenses.

Not sure it is worth that much effort though. Some numbers really are close percentage wise..
20000Lux/ 55 = 363.6 PAR
20000 Lux/ 50 =400 par 9% more
20000Lux/ 40 = 500 par 28% more

So back to reality.. personally for your 22,000 LUX I'd "err on the high side" BUT you would need to add what % (or really what ratio) of blue to white you measured.

I was temped to suggest the Actinic/Daylight number at 38 but 45 may be better. Again depends on your percent blue to white.

479 par using 45 bringing us full circle to your orig post.....

hello

thanks for the answers

so according to you, I repeat approximately, I can leave my parameters 100 blue and 40-45 white?
no risk of coral burns, moreover with the lenses removed?

Cordially

 

[oreo54]

hello

thanks for the answers

so according to you, I repeat approximately, I can leave my parameters 100 blue and 40-45 white?
no risk of coral burns, moreover with the lenses removed?

Cordially

Err.. no I was just trying to show how to calculate par from lux. Nothing whatsoever to do with the effects of that par.