Cheap LUX meter to calculate PAR and DLI

Hi, i had the idea to buy a cheap LUX meter to calculate the aproximate DLI and PAR. I see people are doing that. Some guys alrady calibrated some meters from The apogee PRO devices. ChatGPT says he can calculate the data for me, it just needs the LEDs SPD data and i have it. My LED is Mars Hydro SP250W, perfect for 2x4space. The PAR meters are sooo expensive, i just cant afford them, so i thought this would be a solution, better that nothing at all… Im wondering what would be the calculation error from LUX to PAR even if the Ai calculates it from the SPD data… i thought if the error would be some 5-10% it not so important i could just adjust the height with lets say 10% reserve… What do you think about this? If i give the plant plenty co2 the error woudnt manifest so much becayse the plant will have more power to use the light and temperature…

If you have a phone just download the Photone app. It will give you a very accurate reading instantly with no math or crazy crap like that.

It’s been compared to high quality meters and has proven its worth.

Works with Android and that other ancient tech… peaches or apples or something.

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noup, photone on my android is just a garbage… On iphones its a different story…

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I started out using a lux meter about 5 years ago and used the conversion calculator on horticultural lighting groups web site and came up with a chart that I used until recently.

It may not be as applicable to your light but though I’d share

I recently got this par meter for $120 and using their ppfd charts and hanging height it seems to be pretty accurate.

The other day a friend was over and he had the Photone app on an android and we check it and it was not even close so we used my meter to calibrate his phone app.
I have the app on my iPhone and it was close to within 5-10%

This is all I could find on your light regarding PPFD numbers

Hope this helps


thanks a lot :slight_smile:


Photone and android dont mix. If you have android, use “PPFD Meter” app.

Choose your settings, light source and light duration. Can also set high and low DLI settings to return a color for easy visibility on where you are.

No diffuser needed but your phone needs to be new enough to have the hardware to read the light.


That’s sucks. It works great on my android. Good luck.

I have the s24 ultra. Guess that’s why it works great for me.


Yeah, I had to buy a new phone as mine didn’t have several of the inner workings to use even a level app. Did not have a potentiometer?? Couldn’t use any astrology apps either. I grabbed the S22+ and can now use alot of apps I could not before.


Love my Photo-bio meter

PPFD meter with the uni-T lux meter.

Connects via bluetooth, allows you to view the phone / readings, while the meter is under the light.


Migro review…

Migro Uni-T

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thanks, good video, helped a little bit :slight_smile:

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