Light intensity

Delps8 said:

If you're using the PhotoBio, the Apogee paper might give you some insights into the potential weaknesses in the product. IIRC, there were concerns about drift? Dunno.

If you've got an iPhone, check out Clear Sky/Clear Sky Calculator. Apogee publishes it but I don't (recall) seeing anything that would preclude using it for other PAR meters. Big point is to make sure that the sun is overhead when you take a reading. Phone sensors are not designed to read well off-axis (hence the kludgy diffuser that Photone requires on iOS) so an AM or PM reading might give you bad results.

I'm with you 100% on "the best" - when I see that/hear that in a discussion, I consider that a "warning label" that things will soon devolve into people talking past each other.

Bluelab - amen. Money well spent.

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Hollatchaboy said:

Nah, I got an android. I wish there was a way to calibrate the light sensor on the phone, or a third party sensor, that could plug into USB port, like my digital scope. If that uni - t, works with ppfd app, through Bluetooth, that's game changing for me.

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Delps8 said:

Good. Glad to hear that!

[edit]

Just checked it out and that app is Android only.

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Delps8 said:

Thank you for posting this. If the app does PPFD maps in real time, that's excellent.

I create a table like this in my grow journal (Excel). In this case, I did 19 samples under my Growcraft X3 running at 280 watts. The standard deviation for PPFD is 126 and for DLI is 6. Those are pretty good since it covers the width and breadth to the plant in my tent.

View attachment 5342467

The Apogee has a sample feature where I can take a reading by clicking a button on the display unit but then I have to scroll through the display and type the values into Excel. Or I can create a Note in my iPhone, put on a headset (!), and dictate the readings. Ugh.

It sounds like the Uni-T + PPFD Meter combo would do away with all of that hassle. Heck, if it's an iOS app I can probably run it on my laptop.

That would be a great combo.

Anyone wanna buy an Apogee?

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Hollatchaboy said:

Nah, I got an android. I wish there was a way to calibrate the light sensor on the phone, or a third party sensor, that could plug into USB port, like my digital scope. If that uni - t, works with ppfd app, through Bluetooth, that's game changing for me.

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Hollatchaboy said:

Nope, but I think I might try the uni-t. I've had the ppfd app for about 2 years, but I was told it didn't really work. At least not with my phone (galaxy 21), but I liked the app for the dli conversion. If it works with the uni-t, that's the route I'll go.

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1212ham said:

We know you want to compare it to the Photobio.

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HydroKid239 said:

Whatever percent you move up on the light, add half that percentage to your feed because it will eat more. I made that percentage up, but don’t it make sense? Lol

On a serious note:
I would still be feeding veg nutes for another week or two before moving to straight bloom feed. Your leaves will thank you later.
I would have that light at 100% by now as well. As close as you can get it without stressing the plant out.
Most ppl won’t lower the light so close, but those are the ones who also feed less (50-75% of the feeding dosage). More light calls for more food, and gets you more yield in the end. Depending on the strain, the difference could be massive.

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