Cheap LUX meter vs Apogee 210 I rented

[05XRunner]

.

I rented the Apogee 210 from BRS and it came in today. Someone also mentioned you can use a cheap LUX meter to get par as well by taking the LUX and divide by 60.

I bought this meter

https://www.amazon.com/gp/product/B018QLIVSC/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

 

I took all my PAR readings with the Apogee unit I rented first.

Then i put the LUX meter in ziplock bag and tried to hold the bag as tight as I could against the sensor to try and get a accurate reading.

At first I tried the divide by 60 and the number was WAY low. So tried a few more divisions and found using 30 was pretty much spot on with the Apogee.

Here is the numbers I got. the red are from the Apogee and the green are the LUX meter divided by 30. I checked the number a few times in each spot and the readings came back +- 10lux on the unit so close enough. I had the unit set in M mode of 20,000 LUX since my numbers didnt go above that. you may need to set it to 200,000 if you have lights turned up more.

Now this is doing it under a Radion Gen2 pro with the Diffuser panel. I am not sure if would get same results with other lights but this would probably get anyone in the ball park of PAR numbers I think.

 

par levels by jon duboy, on Flickr

 

 

[Lingwendil]

That's really interesting! I may grab one now.

[Tamberav]

Did you do the conversion for your par meter? It says: The MQ-210 quantum meter is designed for underwater PAR measurements and already applies the sensor's immersion effect correction factor to the meter readings through firmware. The meter is excellent for all light sources, except LEDs, where post-measurement correction factors need to be applied to achieve accurate readings. 

On 1/3/2019 at 5:46 PM, 05XRunner said:

.

I rented the Apogee 210 from BRS and it came in today. Someone also mentioned you can use a cheap LUX meter to get par as well by taking the LUX and divide by 60.

I bought this meter

https://www.amazon.com/gp/product/B018QLIVSC/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

 

I took all my PAR readings with the Apogee unit I rented first.

Then i put the LUX meter in ziplock bag and tried to hold the bag as tight as I could against the sensor to try and get a accurate reading.

At first I tried the divide by 60 and the number was WAY low. So tried a few more divisions and found using 30 was pretty much spot on with the Apogee.

Here is the numbers I got. the red are from the Apogee and the green are the LUX meter divided by 30. I checked the number a few times in each spot and the readings came back +- 10lux on the unit so close enough. I had the unit set in M mode of 20,000 LUX since my numbers didnt go above that. you may need to set it to 200,000 if you have lights turned up more.

Now this is doing it under a Radion Gen2 pro with the Diffuser panel. I am not sure if would get same results with other lights but this would probably get anyone in the ball park of PAR numbers I think.

 

par levels by jon duboy, on Flickr

 

 

 

[05XRunner]

11 hours ago, Tamberav said:

Did you do the conversion for your par meter? It says: The MQ-210 quantum meter is designed for underwater PAR measurements and already applies the sensor's immersion effect correction factor to the meter readings through firmware. The meter is excellent for all light sources, except LEDs, where post-measurement correction factors need to be applied to achieve accurate readings. 

 

No and for my use the small amount of difference in what the par might be I am not to concerned about. 

[mcarroll]

You kinda got the approach wrong....

 

You use BOTH meters to generate measurements from the same spot on the tank.  Then you use the measurements to create your conversion factor.

 

50 or 60 are generic approximations used for estimating....which is for folks without a PAR meter but who still want to have a number in PAR units for whatever reason. 

 

There's no really good reason that I know of for this conversion to be a requirement for hobbyists, other than quite a few folks are familiar with PAR but haven't heard of lux.  If you have a lux meter, just get measurements in lux and use them in lux.  That's what I do.

On 1/3/2019 at 6:46 PM, 05XRunner said:

I am not sure if would get same results with other lights

You would not.  Different light setups will have at least slightly different conversion factors.

 

FYI, I think there was a misquote from Apogee's site above....they say this about your meter and the immersion correction factor:

(emphasis mine)

Quote

*The MQ-210 [...] Underwater Quantum Meters already apply the immersion effect correction factor to the meter readings through the meter firmware. [...]  These sensors do not need post-measurement corrections applied to their measurements.

But your lux readings seem like they may be off....perhaps due to the immersion effect. 

 

To be sure, I would suggest measuring with the Apogee as close to the water surface as you can and then measuring  with the lux meter without a ziplock just above the water surface. 

 

(If the PAR meter is accurate in air, it would be ideal for both meters to be used just above the water level in exactly the same position as one another so the measurements will be a lot more comparable.)

 

Try that to see what you get.

 

Also check out this reading on the topic:  

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

[05XRunner]

i did a test both right at water surface above it. with my conversion the LUX meter was 600par and the apogee was 615

[mcarroll]

I think I saw that you're getting the same feedback on two forum sites.  Tell Salty I said HI!  😄

 

You can get >100,000 lulx readings in the tropics or at high elevations.

 

Unless I'm mistaken, it's Summer where you are....I have no idea what your altitude is, but you'd have to look up reference daylight levels for your area.

 

Here's a general reference:

https://en.wikipedia.org/wiki/Daylight#Intensity_in_different_conditions

 

Intensity in different conditions[edit]

Illuminance	Example
120,000 lux	Brightest sunlight
111,000 lux	Bright sunlight
109,870 lux	AM 1.5 global solar spectrum sunlight
20,000 lux	Shade illuminated by entire clear blue sky, midday
1,000 - 2,000 lux	Typical overcast day, midday
<200 lux	Extreme of thickest storm clouds, midday
400 lux	Sunrise or sunset on a clear day (ambient illumination)
40 lux	Fully overcast, sunset/sunrise
<1 lux	Extreme of thickest storm clouds, sunset/rise

For comparison, nighttime illuminance levels are:

Illuminance	Example
<1 lux	Moonlight,[3] clear night sky
0.25 lux	A full Moon, clear night sky[4][5]
0.01 lux	A quarter Moon, clear night sky
0.002 lux	Starlight, clear moonless night sky, including airglow[4]
0.0002 lux	Starlight, clear moonless night sky, excluding airglow[4]
0.00014 lux	Venus at brightest,[4] clear night sky
0.0001 lux	Starlight, overcast moonless night sky[4]

For a table of approximate daylight intensity in the Solar System, see sunlight.

[05XRunner]

seriously you live 2 states below me and you say you think its summer where I am. 

 

[mcarroll]

thought someone mentioned australia....musta been another thread.  😄

[nanoreeFan]

OK I followed 05XRunner's info and bought  his Lux meter. Got the same results👍. Thanks for sharing 05XRunner ......great way to save some money, apprecaite it.