If it’s stressing for you, don’t look at the numbers. By 1-2 months, keto is supposed to become intuitive and just second nature. I watch my numbers, because I love statistics and tracking, but I won’t let myself getting upset by the actual values. You just can’t force the processes in your body to conform to your wishes. And keep in mind that ketosis is just a byproduct of feeling good - granted, ketones are the fuel on a ketogenic diet so there is some association with feeling well. But blood ketone levels of .3 to .8 after months and months on keto (for some this comes way earlier) are perfectly normal even if you eat the cleanest keto diet. This is simply because your body learns to produce ketones according to its needs (meaning becoming a more efficient fat and ketone burner). I personally haven’t observed a change in my blood ketones as I’ve stated, but everyone is different. I know people who have never had a reading of more than 1 mmol/L, and they are z-carb, meat-only ketonians. I believe @richard has also repeatedly stated that he has relatively low blood ketone readings below 1 mmol/L.
Test Breath Ketones without a Ketonix (using a cheap breathalyzer)
I’ve got a lot of variation in my meters. My least sensitive one will just start to read 0.01% BAC when my most sensitive one reads 0.04 - a point where I’m solidly in ketosis and typically showing 0.8 mmol/L by blood. Curiously they ramp up at different rates and all read the same in the 0.10 to 0.12 % BAC range, which I typically only hit after 48 hours or more of fasting.
Yes, I know you’re right about the body adapting and producing ketones as needed, and I’ve been keto for at least 4 months.
I’m finally seeing the correlation between the protein and insulin load as well and planning to be more careful with my macros, although not obsessed I love the fats, and the protein is far too easy for me to overeat.
As long as I can see my BG readings come down over time and have some more NSVs and or weight loss, I’ll feel more confident. The feeling that I am regressing is what gets me rethinking (overthinking) as usual.
OK, this too is good to hear. After the BG reading of 106 at 1230PM, and then having a 0.0 reading on the AT6000 I was feeling pretty frustrated.
I haven’t overdone the protein of late and I have been consuming (too much?) fat as desired.
My understanding is that elevated cortisol levels from extreme amounts of prolonged stress can also be an inhibiting factor for ketosis. So, with all that is going on in “my world” so to speak, I shouldn’t be so surprised. I was just hoping for something else in life to be happy about!
But God is good and so, I am always happy for that!
I have the original ketonix and it still works. I like blood testing better. I cant stand having to figure out is it yellow or green. (as I would say it’s yellow - green) And then the flashes, I cant figure out what they mean. The website doesnt show anything for the older model. I have found a few videos and websites that help. The new ones seem totally awesome. But I like blood testing. It is so accurate and gives you a real number. With the keto mojo I can get strips for a buck a piece. I can tell by how I feel now if Im in mild or deeper ketosis.But seeing the numbers really motivatse me. For example I just started doing a 4 hr eating window and saw these results today 3.9 ketones and 97 blood sugar (a little high on that one but stressful day at work) I have 2 breathalyzers too. I want to do a few testing with all of these. When I do I will post it.
Good chance you just aren’t doing it right too. I had that issue at first. I got the technique down eventually though. My wife still has problems.
My understanding is you blow most of the air out of your lungs and then blow into the ketonix. Maybe I mispoke. The ketonix did seem to match with my blood ketones - after I found a chart to give an idea of how they correlate. I just like the exact numbers. (comes with the territory of being a nurse for 28 years…lol) That way I can see what I ate the day before and how it affected me.
I just had my husband try the AT6000 after a slow…two beers, he blows a 0.02
As for me…nada. 0.0
I just stumbled on this myself and was thinking about building one. (the Arduino Ketosense project) Have you built one yourself? If so, how did it do?
No sorry, I did not build one of these. I bought a pack of sensors to experiment with but life got in the way - as usual! 
After reading this with interest earlier in the week, I got a ‘cheap’ breathalyser from Amazon, and I’m blowing either 0.02 or 0.03. My boyfriend gets a big fat zero, he’s not keto (and it takes him longer to get a result - is it stopping sooner for me because it’s registering the acetone?).
New here :)
Yes, with most of these breathalyzers higher readings come back faster. The highest readings they are capable of come back almost instantly. I suspect the way they work is the sensor trips after crossing a cumulative saturation threshhold and the result is determined by how long it takes. There is quite a bit of variability in these meters so your 0.03 might mean anything from modestly in ketosis to quite deeply in ketosis. But keep tracking and you should get a sense of where you are at and what foods you want to more carefully restrict because they drop you low and what foods you can indulge with less concern. Note, there tends to be hours of delay between eating a food and it dropping your level and many more hours to rebound. So tracking is easier/more effective when you only eat potentially problematic foods infrequently. Combinations can matter too, mushrooms with bacon might be ok while mushrooms with lean chicken breast lower your ketone reading.
Has anybody else had prescribed eye drops knock you totally out of ketosis and at the same time raise your blood glucose 40-60 points and it stay up?
Has anyone given you the advice to exhale most of your breath, before beginning to breathe into the AT6000 unit? You want to be consistent, but I find if you inhale deeply and blow directly into the device, it may register zeros. But if you breathe out first, and only leave just enough air in your lungs to have enough to blow into the unit, it gives a reading. And breathe slowly, not quickly, into the device. Also develop a consistency.
OK, yes, I’m doing it that way now and I am getting a consistent reading of 0.02. I also checked by blood ketones the first time I registered a 0.02 and I think I had a 1.6 on the blood ketone reading whilst showing the 0.02 on AT6000.
Thank you for the advice, and I know it’s not crucial to be checking this all of the time. I was just hoping for something, a device that could give some indication of ketosis without my spending so much on test strips. Also, if it is fairly reliable, it allows for much more frequent tests to check any correlation between foods eaten and also BG readings at the same time.
So, I “blew a 0.03” this morning on my AT6000, and sadly, I realize that I had no cheese yesterday 
But, but, but…I LOVE cheese!
Pretty much any reading on 5hese should probably be considered positive for ketosis.
Just to clarify why I put the question here about the eye drops, I went from 93 blood glucose and .05 on cheapest breathalyzer and .03 on a little more expensive one to 160 blood glucose and .00 on both meters. Stopped drops, blood glucose down to 133 and getting a very minimum ketones on the cheapest meter, nothing on the slightly more expensive.
For all that’s holy, please stop obsessing about numbers, especially ones of a 15 Dollar device! I fear this number tracking is not doing you any good. You don’t chase ketones, you chase progress in terms of your personal goals you want to attain with this WOE (weight loss, diabetes reversal, life quality improvement etc.)