Watered again with same solutions. Runtz x Sour Bubble seedlings still getting the 0.4EC, 907 Blue Genes x Shiskaberry 3 and 907 Blue Genes x NL #1 already in 3" cubes getting 0.9EC. pH 5.51 which I actually trust now and didn’t verify with dropper solution or ph paper.
I moved the weaker 907xShisk onto a small tray and placed it up on the ~200 PPFD shelf rather than the ~400 PPFD lower shelf. The lower seedlings for the most part are taking off now, but that one seemed stunted so trying to take it out of the fast lane for a while.
I’ve done some basic comparison of these 3 PAR measurement solutions:
Photobio Quantum PAR
PPFD Meter App + Uni-T UT383BT
Photone App + Google Pixel 7 Pro No Diffuser (the app requests diffuser paper be removed on this phone)
For the veg light, I just set them side by side to get an idea. How far off in the weeds are they? They are all close, astonishingly so. The most error I observed was about 30 at 650 ppfd (5%), with both the photone app and the PPFD Meter App reading slightly lower than the Photobio unit. I’ll be really curious how these compare under the flower light (XS1500 Pro) and relative to the Apogee 510. But all 3 agree, at least on the veg light, to within 5%. This is just a simple sanity check, when I compare closer I’ll ensure they are all in the same physical spot, same altitude, correct LED flavors selected in the apps.
I also did a teardown of the Photobio meter as well as the UT383BT. I’ll spend some time writing this all up to go in the thread I make. Here’s some teasers if there are technical folks eager to see.
Preliminarily, I’m suprised the Photobio is as sophisticated as it is. It’s pretty nicely executed. They have a color-channeled ambient light sensor (so they are doing spectral compensation) as well as a photodiode, all with bandpass filter. The primary microcontroller is the larger IC there, MSP430. Makes sense to integrate the measurement capture in the detector head. The battery/display box is essentially just a dumb display with LCD driver and buttons.
The UT383 ($30) is basically what I expected to find in both - a large-area photodiode with filter assembly. It has a surprisingly nice circuit design for the front end TIA with 4 gain ranges. I can’t believe anything like this can be sold for $30 retail price. This thing probably costs $5 to make. Just blows my mind sometimes.
Cheers guys, have a great weekend.
I’ll be moving the Runtz x SB up to cubes this afternoon or in the morning.