I do think the BrewJ may have caused the heat to rise a little in the room, but just a few degrees
it most likely did. a brew j is a heat pump, so it cools the beer by kicking out the heat into its surrounding enviro, i.e. the room.
my only gripe would be I can't see what's going on or access the spigot to get a sample for gravity readings
if it's important to you, i bet you could figure out a way to cut open the cover, sew up the edges and create a flap.
however: please consider making it not important to you, AKA stop taking (constant) samples. wait for visible activity to die down completely (no more air lock bubbles, krausen gone, etc.), wait another 3 days, then take your first, and ideally only, sample. what's the point of knowing that yesterday you were at 1.042, and today you're at 1.038? are you going to do anything differently? the yeast know what they're doing, let 'em finish their work. each sample taking = risk of oxidation and/or infection (small risk, but risk nonetheless).
i mean i get it, it's fun to interact with the brew as it's developing, but i compare constant sampling to helicopter parenting: it makes the parent (brewer) feel more at ease, but isn't in the child's (beer's) best interest. let go...
on that note, been reading mixed reviews on going the refractometer...
the good: only a few drops are needed to keep taps on gravity
the bad: complicated with conversion charts and temp (how come they all come in Celsius...)
was reading that the good old hydro is the best bet for accuracy and simplicity
i love my refractometer on brew day - so quick and easy to get OG, no wasted wort, etc. i also take gravity on first runnings, lets me know how my mash went.
where have you read about temp affecting a refractometer? most nowadays have auto temp compensation (ATC), even
the cheap ones.
refractometers become complicated once alcohol is present. you need to use
a calculator to correct your readings, and even then it's only a best-fit estimate. so being lazy i don't bother and just use a hydrometer - when i bother taking FG at all. i often skip it if the fermentation went as expected, i'm pretty confident that the beer ended where it should. the difference between 1.10 and 1.012 is imperceptible to me, so...
If I had a spare $150...might consider the Tilt Hydrometer...pretty darn cool
looks cool indeed. can't say it's at the top of my gadget shopping list, but i certainly wouldn't throw it away if it was given to me. i've been reading that krausen can cause readings to be off. i think the main value of the tilt isn't to get exact gravity readings, but rather to see the trend. once it shows several days with no change in gravity, your beer is ready to package.
unrelated, a cheap stir plate:
https://www.amazon.com/dp/B072K24X5P/. If you're a DYI kinda guy and are handy assembling simple devices, you can build a stir plate quite easily using a computer fan, a potentiometer and a case of some sort (like a cigar box).