If were me, i would calibrate regardless. I trust a reading that is verified and calibrated to over photone uncalibrated. Especially if they dont match
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Not a bad idea, after all even if it’s not perfect it will be a good idea. I used Photone for a year. Just keep an eye on the plants and learn your lights. 
You don’t need a meter to grow, just watch the behavior. 
@Bigcbud
When it says it’s calibrated just hit got it. It will still take you to the calibration settings.
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I agree as well. Meter is not needed. I can do it by sight or by how much they prey or the color of the tops. I do believe pushing them as hard as some people do is not needed. I try to stay below 900 at highest regardless if they look like they can take more. Although not needed, i still prefer to keep tract for the data. Not a fan of winging it. This is how we get better by logging the data. My buddy bought a brand new apogee mq500, surprisingly did not match the chart. Was good 10% higher then the chart. For this reason it gave me alot of doubt. But by calibration, you atleast have a baseline to compare after a grow.
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I just went through this too, as I am sure many many have as well.
I am running an EVO6. While not scientific, I did some careful measurements of my light.
It’s mounted in a 4x4 ACI tent. Initially, I used my iPhone14 running Photone v3.5.1 with diffuser, full spectrum LED setting, and factory calibration. I took a bunch of measurements using the published ACI par map document at 12" and 18" heights. What I came up with was that the Phontone was indicating PPFD values at approximately 68% of the published values. So Photone was LOW by 32%. This difference was quite consistent at various spots around the par map and at various heights.
Then I used the apogee MQ-500 to take equivalent measures (like @Low showed in his thread) with the app. The app was again consistently lower, but by a much lesser amount. The app was on average measuring 96% of the apogee. Again, the differences were quite consistent regardless of area under the fixture and height.
So I used the apogee to calibrate the Photone app, since I think I trust the sensor and the “real world” measurements I took using my fixture inside my tent. Since I was using the meter on loan, I needed to return it fairly quick, and I didn’t conduct extensive measurements, but it does appear that my fixture in my tent measures about 72% of what the ACI par map says.
When my current grow is over, I want to borrow the apogee again, and do a bit more scientific measurement of my EVO6, but for now I’m pretty happy with the Photone app calibrated with the apogee. And I definitely LOVE the EVO6 - I’m so glad that I saved my money up and bought a great fixture. I can run it at less than 100% most of the time and get more than enough PAR in my tent.
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Yeah for some reason when I started the grow light wasn’t something I looked into even though seems to be one of the more important pieces of equipment for the grow. What is confusing to me is I generally see people mention that it’s slightly lower than a par reader but mine is double the amount. I did recently see a video where a guy converted a chart to use a lux reader relative to his apogee.
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Hard to say anything without knowing all the conditions. Seedlings need very little light. Around 250 ppfd at that stage. I know i said i can go by look, but i also know my conditions to better assist. It looks dry but to me has the overwatered look. Which will cause the pale look. Sorry im not much help. Easiest way to do seedlings is using a flourescent with around a 4500k color at about 2 inch from plant.
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No need to be sorry I know there are many factors when diagnosing a plant and to be frank I don’t ph or anything. It did suffer from overwatering and growing came to a halt. I’m letting the soil dry up slightly and only doing a misted cup until it touches the sides to try and prevent from stunting this auto again.
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Im not a dome guy, but for me i like to get the soil wet, just shy of runoff in a solo cup, sow the seed, and not touch it for about 5 days. Then as u said, use a mister, like 5 sqeezes a day after that. Also would recommend 24 hr of light during this stage until they are into the veg stage.
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So you don’t even bother with humidifiers?
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I grow in a basement. So humidity is normally higher. I only need a dehuey for flower
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What light, what power level, and what height from crown/canopy?
My android app never worked (diffuser?).
I bought the Unit UT383-BT.
My meter reads LUX.
HLG calculators used for conversion LUX to PPFD.
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Currently using two spider farm sf1000 one seed at germinating waiting to sprout and another at seedling that you saw.
The seedling is at the recommended 24 inches per their chart at 60% getting a reading of
And then the seed waiting to sprout is at same height for 50% with a reading of
The tent is a 2x3x5 and there’s a fair amount of distance between the two
Even looking at their max values for pfd at 100% at smaller heights I’m still higher in pfd.
Which I’m sure having two lights will maybe amplify one another but I’m not sure. Low gave me a rough estimate on pfd for the center of two daisy chained and not inside of a reflective tent. My setup is a lot different so I don’t really have a rough estimate to go off of.
The plant is looking more green today than before and I believe I made adjustments to what you’re seeing now.
YouTube videos with MIGRO (?) he measures footprint/sq area, sums the meadurments, does average and then converts.
I can use HLG stats for my light outputs and do math.
The Kil-a-watt meter and UT383-BT measure actuals, not advertised.
HLG is better than my china cheapies (not cheap costing or use).
I can measure the difference in all equipment and settings used.
Watts x efficiency x hours on x.0036 = DLI (maybe)
(500watts) x (2.8) x (11.5) x (.0036) = 57 DLI
HLG 350R
330 x 2.8 = 924 PPFD
900 x 11.5 x .0036 = 37 DLI for flowering 11.5 ON/12.5OFF lights.
Maybe I have it right for my lights.
Ended up buying the meter in this video but I’m unsure by the details section of his video talking about a conversion. Any chance you can look at what he meant by that.
This was the conversion
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I’m not a light tech but I don’t agree with the statement 40000lux or 1000ppfd 
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My meter (the UT383-BT) reeds 0-200K LUX (not 400K).
The brightest daylight I have measured, so far, was 150KLUX.
The HLG lights at 5 inches, will OL the unit (out of limit).
For $30.00, don’t forget to update us.
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I think he was referring to the charts provided in the video I linked. The guy compared his apogee with an Amazon meter that reads lux and charted a graph for people to reference. What I didn’t understand was his note on a change in conversion, was hoping you could shed light (da dum tiss) on that.
I am talking about something different but it’s all good I’ll try that method and see if it works. Thanks man
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