The readings that I'm getting vary significantly. Outdoors, it reads 410 ppm at calibration. In the tent, where it sits on the top of the res, it's 410 and 420 but I've seen it as high as 800, IIRC. I assumed that was due to the plants. I haven't made a point to check it on a regular basis because it's, frankly, just a curiosity ATM.
Re. sensor cost - I'm sure there are a wide variety of sensors and a big part of that is that it's not just something that measures CO2. A huge issue is how robust a device is, for want of a better word. People mock the $800 toilet seat - sure some of that stuff is worth mocking but I also know that a lot of what drives the cost of a product is the conditions in which it will continue to function. The sensor that Inkbird is using is the same type of sensor that Pulse puts in the Pulse Pro. I didn't find any tech data on this device but the Inkbird CO2 controller is stated to be ±30 PPM and the PulsePro is ±50 PPM.
Maybe the best way to think of it is that it's a ballpark indicator.
"white label products" - agreed. I see lots of that. No engineering, no product differentiation, just marketing. Caveat emptor.
I might try a DIY. Dunno about a bucket but would a milk jug do the trick? Just mix everything up and put the milk jug in the back of the tent.
Agreed. Human ingenuity. And having kids that'll work for cheap.
That's all good info. I have learned a lot about Co2 sensors over the past week, yet likely still know nothing. I did "know" that the "Inkbird" contained an NDIR censor. But didn't know whether to believe it. I read a review on another detector on Amazon that claimed to have a NDIR and apparently it didn't when torn down by the reviewer. I should've saved the link, but didn't.
My meter did vary significantly as well for the first 24 hours-ish. Then it just got stuck and would never change no matter what. Even after a power off/on. Like yourself, I mainly got it for curiosity, so I wasn't heartbroken when I sent it back. I chalk(ed) it up to being a $35 meter vs a $300 one. But I believe it got up to around 1200PPM at one point. And if it was working as intended CO2 levels were high-ish with the bag until my exhaust had to kick in to remove heat. Which all made sense. During flower it is likely more tricky as most of us need/want to kill smells, so you would have to exhaust through your filter more frequently.
What we need is someone with both the inkbird and a more expensive unit to compare. Interesting about the Pulse Pro having the same sensor. I have a buddy who wants one and I keep telling him he could use that $$$ towards something else to improve his grows.
I would mock the $800 toilet seat.
As far as the milk jug, that's actually how I started to play with it. I filled the jug with the solution and poked holes in the cap. Shook it up every couple days. I put it on the tent floor next to one plant - a GSC auto- and that plant yielded 15 oz dry. Other plants were smaller. So I started messing with the yeast bombs and trying out the bags for more fun and my grows just yielded fairly big. 20.5, 13.4 and 9.9 oz per auto last run.
Fully aware that it could be a total placebo thing, that's why I continue to use them - out of some superstition. Or the timing of playing with it just coincided with me becoming a better gardener. Or both helped?
