The BeerBug folks were kind enough to send me a replacement BeerBug (with a green LED instead of blue) in view of the problems I had with my early model.
I happened to have a beer fermenting so I tried it right away, but had some issues likely related to the line holding the torpedo weight being too long so that the weight partially rested on the fermentor. And the beer was about done fermenting.
After shortening the line, I tried in again in a carboy of water to make sure things were sorted.
Normally the BeerBug is supposed to go to sleep after not talking to the app after a while, but in this first trial it never slept: the LED didn’t go to more the more dim flashing that indicates the low-power sleep mode, and the battery didn’t last very long. Turns out you can soft-reset it by pulling the battery for a moment (it saves your data through this), but I didn’t do that this time.
Another trial of leaving it in water (starting with a new battery) for a while worked out much better:
There is some drifting with the mild temperature fluctuations, but if you look at the scale you will see it is only about 0.04 gravity points. The spike in mid-morning of May 12 is when I squired a little StarSan down the snout of the BeerBug just to see what sort of impact it would have. Not too bad. Overall this BeerBug seems pretty stable and definitely much better than the last one I had.
I look forward to trying it in a fermentation.