I don’t think it’s a good idea to take any deep breaths before sampling. That just fills the lungs with room air and lowers BrAce concentration. You may find it a better technique to exhale partially before continuing to exhale fully into the device. I find compressing my abdomen and pushing up on my diaphragm helps a lot to get the acetone out of my lungs.
Anyone heard of Keyto breathalyzer?
Acetix
(Michael)
#22
When I say to take a few deep breaths I mean to breathe in and out through the nose only to make sure one’s brain blood supply is well oxygenated before blowing into the device.
I can take multiple samples in quick succession with very consistent results.
I think if one has an established sampling technique then all measurements will be relative to each other.
Different people would probably get different results using the same device even if all the other variables could be controlled for. The device is measuring BrAce in PPM for sure; it’s our blowing technique that will determine how much acetone is dislodged from the lungs.
I just carried out a n=1 in testing at two minute intervals:
sitting up as normal: 9.3 PPM
lying down sideways on rigid chair with head and chest lower than rest of torso: 6.3PPM
upright in chair again 11.7 PPM
5 minutes later seated again: 7.8 PPM
12 minutes later still seated 8.0 PPM
Acetone can be dislodged from bottom of lungs by lowering head and chest below torso level. This is better represented when sitting upright again.
Overall it’s not worth the effort really.
Mytmo38
#23
Good day, I’m noticing here that people are confusing the “Ketonix” breathalyzer with the “KEYTO” breathalyzer. These are 2 totally different devices. I love my “KEYTO” breathalyzer pen, well worth the cost of $99.99. As with any desired product, what works for One might not work for another.
amwassil
(Michael - When reality fails to meet expectations, the problem is not reality.)
#24
No confusion. Several of us here happen to use a Ketonix and we simply branched off to discuss some issues with that particular device and BrAce measurements generally. Not too many (2?) using the Keyto device. The OP asked for input on the Keyto device and comparisons to the Ketonix seem apropos.
dub
(Boston_guy)
#25
I have a Ketonix, and for whatever reason never got into the habit of using it. It’s easier to have Keyto in pocket, talking to phone over Bluetooth, than a USB device with a long cable needing to sync to a computer. When initially using it, I was doing about a dozen readings a day.
As for precision: 8 levels is plenty for behavior change. I’m still chasing 8 
amwassil
(Michael - When reality fails to meet expectations, the problem is not reality.)
#26
My Ketonix is Bluetooth, has a cylindrical battery pack and ‘talks’ to my iPod app. It’s very convenient to use.