You ever look at this kind of thing? Seems like you’d have an easy time of it with one of these as a DIY since you probably have the other Arduino stuff:
There’s also the TSL2561, slightly different:
https://agsci-labs.oregonstate.edu/openslab/2018/04/27/2018-4-27-tsl2561-or-tsl2591/
Purchased a semi cheap light meter UT383BT based on info in this thread. Might be of interest
I’ve been satisfied with the results from my $35 lux meter (MAKE SURE TO BUY BLUE TOOTH MODEL)
Interesting read and videos. Results match what manufacturer (ViparSpectra) claims.
I’m using Android FWIW.
Just my $.02
@Dirt_Wizard @JOHN1234 I’ll take a look at these tomorrow, thanks for the leads 
@potpotpot good thinking 
They are continuing to grow, faster now. I do have some concerns about the size and less-than-ideal health of the leaves. The Runtz x Sour Bubble are all pushing their helmets above the rooting plugs.
Are you guys under the impression that I’m running too bright with the lights? Or is this a nutrition issue? I dimmed them a little bit after I took these pictures.
I have never seen such small full leaves. When using the two 20W shop lights I didn’t have this issue. Of course, I’m not doing anything the same so essentially it could be all or any of the things. Temperatures all look OK, it’s not like they are cooking alive or frozen. Air is about 83F daytime, 68F at night.
Temperature Log:
I’m watering with AN Sensi Cal Mag Xtra at a rate of 2mL/L. This is the calculated solution elemental properties.
AN Sensi Cal Mag Xtra:
MegaCrop recommends 0.53g each part A and B for veg. That (with no Cal Mag) looks like this,
MegaCrop Veg Recommendation:
Anyway, I think it’s important that I get some answers for the PPFD question sooner than later to rule that out. Then there’s the question of spectrum, these are 6000K LEDs. I’ll get a solution to that ordered today but I’m probably going to mix up a new feed liter of water with some of the MegaCrop. I don’t like the fact that there’s such limited nutrition available at this point.
I’ve got these in my Amazon Cart:
Any input?
Good morning @FieldEffect
That megagarden fits tight tight tight!
Hard to say if your light is too bright w/o a meter you trust but I’d wager its not too weak either b/c they aren’t stretching hard for it. Either way I’d dim it slightly until you green them up. IMO you should be using your veg nutes as a base and calmag only if you think you need it. Start low n’ slow
I’ve read great things about the photone app on iphones, ie; just as good as expensive meters. Maybe pick up a cheap used iphone just for the garden and posting on overgrow 
@potpotpot those syringes are a must have imo… I use my 150mL almost daily.
edit: looks like its time to gives those larger ladies some new shoes!
pot 'em up and feed em! quicker the better.
you could use a good lux meter for your 6K Quasars, but it won’t read your flower light very well. buying two cheap meters? to me, this is another spot where you skip the nickel-and-dime, and nut up for the quality kit (apogee, etc) 
Yea, it’ll do, I think. I just meant options that don’t cost you anything.
Yea, use her iPhone. Calibrate your phone/app to hers. Don’t ask her though, just do it while shes preoccupied with something. Tell her after.
Get the par meter, the photobio, out of those two options.
Your setting a man up to be injured there sir. 
Haha. I was going to point out that I don’t even have a girlfriend, so careful with my suggestion.
I don’t think the Photobio is a “cheap” meter at all - it’s entry level of the reputable PAR meters. The Uni-T is certainly in the “cheap” category. I think primarily I’d use the Photobio. I’m thinking about getting the Uni-T just to compare things and try with the PPFD app as @JOHN1234 and the orginal poster @The_Lazy_Hippie in the linked thread. I can rent an Apogee to compare them all and post real results. Then I’m out half the cost of an Apogee, have a calibrated (on my actual lights) stand-alone meter solution, and can post real-world comparisons so hopefully this debate can have a test to reference. A real side-by-side of the two (primarily the Photobio and the Apogee) I haven’t really seen done. Lots of phone app comparisons to a PAR meter but seldom the 3-4 real options side-by-side.
I don’t know. I’m going to sleep on it. It’s not like buying an Apogee would ruin my fun money budget I just think that I’d get better value with other things.
Absolutely!
LOL I’ve got a little more sense than that.
I’m soaking rockwool cubes now for transplant…we’ll see how that goes 
Figured I’d just stop typing and thinking about PAR and do the job.
Was surprised I had roots. Quite a few actually. Some of the NLs had quite a few more but hands were wet and so just took pics of the first one pulled.
Just tried to carefully get them down into the holes nice and tight without breaking them.
I gotta say, these plugs plus the rockwool cubes with the holes are pretty f***ing convenient.
Mixed up some 80% nutes and pH’d to 5.5ish. Meter is calibrated, and verified with pH paper and the liquid indicator solution to be between 5 and 6. I’m getting a better meter eventually, trying to decide which. I like the Apera ones, especially the multifunction like the GroStar GroStar® GS4 pH/EC/500ppm/700ppm/Temp (5-in-1) Combo Pen Tester (Gen II). For my needs I think that would be great and easier to manage.
1.623g Part A, 1.626g Part B, 1 gallon RO at 15 “ppm TDS”
Gave them just a splash of the nute water, the cubes had been soaking in RO that was pH’d to 5.5 so I am getting quite a bit of dilution on the first little taste of nutes.
Back home…
I got an Apera PH60 as I saw @DougDawson using his and having great results. It came as a kit with the calibration solution for EC and PH which is nice. It is night and day faster and more accurate than the $30 meter I had been buying for years. I’m a big fan, just need to see how it lasts going forward.
Lookin’ good in there
Is the plan to veg them on the other side in the megagarden?
@FirstCavApache64 How long have you had it? I really like my apera PH60 also, so far the probe has ~8 months on it w/ very little drift in between calibrations. If the probes last a year I think that’s a win.
@FirstCavApache64 The PH60 seems really popular. @DougDawson also uses the Photobio PAR meter I’m looking at.
@NoCal I think for now I’ll veg them on the veg side. Hand water for a while. Nice to hear you like the Apera PH60 as well. Once they get big enough to take clones those will go on the MegaGarden deck. I may do drip or something on the veg side eventually. Lots of learning going on trying to incrementally approach these things and get familiar along the way. We’ll see how it works.
Yeah, I have had mine for years now and it’s amazing. Best meter I have ever owned. I store it right and have not had to change the probe in the 2 years I have been using it. Congrats on the purchase, it was a great choice IMO.
I do recommend that unit. It’s not overly expensive and pretty accurate IMO.
It’s been about 2-3 months I think. If I get a year or more out of the sensor I’m good as well. I used to buy the cheap meter almost every 6 months and have to calibrate every week or it would be way off.
Just sharing (again, maybe?) that Daniel Fernandez recommended Apera. He also advised against “multi/combo” meters (maybe specifically in the “pen” form factor) due to them being inherently more likely to have issues, from a design stand point. I can link to it, but it’s in a forum you’d need to sign up to to see the posts (and it might have been a private message, now that I think of it). The PH60 and it’s equivalent EC pen probe is the one he suggests.
Might not be a big deal, I just wanted to mention it.
I’ve definately heard this. The two tips are somewhat incompatible in terms of ideal storage. Fortunately, the duo is only $20 more than the combined unit. Part of me really likes the simplicity of getting the two measurements at once. The heads are also replaceable, but expectedly, more expensive. That’s another thing I’ll sleep on. I figured it was something that if cared for properly (it would be) wouldn’t be a big issue.
Tough decisions 
it’d be easy to go either way, both on this and the PAR meter. We’ll see how I feel in the morning about both of these issues. 
The fast response definately sounds nice. I sit and watch the pH change with the current meter, feels like minutes but probably more on the order of tens of seconds.
Too bad we weren’t in the same country. I have a bluelab combo meter, and a guardian monitor, new in the box I’d like to part with.
As for the combo meters, I think it also had to do with “interference” of some sort. I don’t know how big of a deal it is, if it is… when it even is. Haha.
My 0.02. I used to handle returns for a store that sold ph/ec meters (only hanna, bluelab, hydrofarm at the time, also 15 years ago ). The returns from highest to lowest were always; combo meters>ph meters>ec meters (which almost never failed). Most returns were due to ppl not storing them properly and just needed new probes.
I’m going to leave the above, but I had a whole rant about how the combo probes cost a lot… turns out the replacement probe for the GS4 meter is only ~$65 which is reasonable imo so I deleted it 
I guess I’d still recommend separate meters if its an option.
