# Free PAR Meter App



## Kubla (Jan 5, 2014)

That's awesome. Thanks for sharing. I'm anxious to try it out.


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## rzn7z7 (Aug 17, 2013)

Wow, this is brilliant and thanks for the tip! I'm not sure I'm comfortable submerging my phone in a bag, but I do have a Seneye and wonder how it compares


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## minorhero (Mar 28, 2019)

rzn7z7 said:


> Wow, this is brilliant and thanks for the tip! I'm not sure I'm comfortable submerging my phone in a bag, but I do have a Seneye and wonder how it compares


For our purposes I honestly wouldn't bother submerging the phone. We mostly care about ppfd at substrate. So it's easy to set your phone on a counter and hold the light you are using the same distance above the phone as your tank substrate is from the light.


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## Eric Tran (Jul 7, 2016)

Awesome! Which light setting did you use? Choosing halogen vs cfl gives wildly different readings.


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## minorhero (Mar 28, 2019)

Eric Tran said:


> Awesome! Which light setting did you use? Choosing halogen vs cfl gives wildly different readings.


My lights are LED and specific for growing plants so I chose full spectrum led.


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## Bettatail (Feb 12, 2009)

+1, it is pretty accurate for LED planted light setup, these LEDs emit light within photosynthesis spectrum range.

Got an apogee MQ510 though, 



Eric Tran said:


> Awesome! Which light setting did you use? Choosing halogen vs cfl gives wildly different readings.


halogen or cfl emit light off the photosynthesis spectrum range, and a smart phone PAR app will pick up the spilled light so the value is bigger than the true PAR, so any smart phone PAR app is better to use on plant LED setup only.


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## Eric Tran (Jul 7, 2016)

Looks like the full spectrum led is only available for paid version on iPhone


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## Bettatail (Feb 12, 2009)

PPFD meter app on android, is good reference too.
for plant LED though.


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## Bucho (Dec 19, 2021)

Yeah, I'm not really understanding how this is supposed to work. The missing step, would be a calibration to a _known_ source. The app even states this. (in fact, the photone app rightfully states how inaccurate the light sensors in phones are) I do not have a known source. So from what I see in the instructions, we're taking some random reading, and then doing a compensation routine on it. The grow light meter app instructions call this a "reference" measurement, "taken under stable conditions". But nowhere does it suggest how (or even that) we baseline the value to something that is known.

What did I miss?


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## jeffkrol (Jun 5, 2013)

Bucho said:


> Yeah, I'm not really understanding how this is supposed to work. The missing step, would be a calibration to a _known_ source. The app even states this. (in fact, the photone app rightfully states how inaccurate the light sensors in phones are) I do not have a known source. So from what I see in the instructions, we're taking some random reading, and then doing a compensation routine on it. The grow light meter app instructions call this a "reference" measurement, "taken under stable conditions". But nowhere does it suggest how (or even that) we baseline the value to something that is known.
> 
> What did I miss?





QUANTUM SENSOR: Clear Sky Calculator, Apogee Instruments Inc.


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## minorhero (Mar 28, 2019)

Bucho said:


> Yeah, I'm not really understanding how this is supposed to work. The missing step, would be a calibration to a _known_ source. The app even states this. (in fact, the photone app rightfully states how inaccurate the light sensors in phones are) I do not have a known source. So from what I see in the instructions, we're taking some random reading, and then doing a compensation routine on it. The grow light meter app instructions call this a "reference" measurement, "taken under stable conditions". But nowhere does it suggest how (or even that) we baseline the value to something that is known.
> 
> What did I miss?


You need 2 apps to make it work. The part you are missing is the lux meter app. This app already takes really good (for an app) readings of lux. I believe the developers of the lux meter app have already calibrated their app to various phone models. You use that reading as your calibration source. I tried this and compared the results to my apogee 420 par meter and found it remarkably close.


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## Bucho (Dec 19, 2021)

minorhero said:


> You need 2 apps to make it work. The part you are missing is the lux meter app. This app already takes really good (for an app) readings of lux. I believe the developers of the lux meter app have already calibrated their app to various phone models. You use that reading as your calibration source. I tried this and compared the results to my apogee 420 par meter and found it remarkably close.


Nope, not missing anything. I called out both apps in my reply.

I guess what I'm saying is, since I don't have another meter to baseline readings to, it doesn't make sense that my phone's sensor would be anywhere near ready to use. You have a calibrated, scientific instrument to compare to. For me, trusting a sensor in a cell phone is a leap of faith. Call me an empiricist. 

I'm using it, but I'd eventually like to find someone local with a PAR meter to take a certifiable reading. I have one tank that's a real trick to keep in equilibrium. It's mostly moss, but with a carpet of E. Hydropiper. I want to pull my lighting levels down to close to the minimum for the carpet.



jeffkrol said:


> QUANTUM SENSOR: Clear Sky Calculator, Apogee Instruments Inc.


I don't understand your reply. I don't have an Apogee sensor.

I think that you're telling me to go out and compare my phone reading to the parameters in this calculator. (which would need to be done at noon in July or August)


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## minorhero (Mar 28, 2019)

Bucho said:


> I don't understand your reply. I don't have an Apogee sensor.
> 
> I think that you're telling me to go out and compare my phone reading to the parameters in this calculator. (which would need to be done at noon in July or August)


Anyway, my point was that the lux meter app is already pretty accurate BUT these are also free apps so your cost in this whole thing is just whatever time you put into them. I have used the photone app a few more times after setting it up and it remains relatively accurate and extremely convenient. It's true I have a par meter to compare it to, but that was just to check and see if it was doing a good job. I didn't use the par meter when setting it up or calibrating it. Is it perfect? No, definitely not. But par meters are expensive and if you have no idea what your light levels are, this app will give you a much better ballpark guess then anything else I'm aware of without an actual par meter.

If you want to use an actual par meter you might contact some local fish stores in your area and see if they have a rental unit.


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## Bucho (Dec 19, 2021)

Yeah, I was actually going to go the LFS and ask for a PAR meter today. 

I mean, don't get me wrong - if this thing anywhere close to works, it's tremendously valuable. I just need a way to verify it, before I trust it too much.

Thanks for posting. Good discussion, actually.


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## minorhero (Mar 28, 2019)

Bucho said:


> Yeah, I was actually going to go the LFS and ask for a PAR meter today.
> 
> I mean, don't get me wrong - if this thing anywhere close to works, it's tremendously valuable. I just need a way to verify it, before I trust it too much.
> 
> Thanks for posting. Good discussion, actually.


You can also google reef2reef photone and get the thread over there (a few hundred posts long now) of people discussing it and people troubleshooting calibration issues.


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## jeffkrol (Jun 5, 2013)

Bucho said:


> I don't understand your reply. I don't have an Apogee sensor.
> 
> I think that you're telling me to go out and compare my phone reading to the parameters in this calculator. (which would need to be done at noon in July or August)


Yes it's a method of checking the accuracy of any Par meter .

Very interesting ..


Model Accuracy | Clear Sky Calculator


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## moke (Jan 4, 2020)

it's a beta app.


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