That occasional whiff of something gone bad in your kitchen that you cannot find with deep breaths.
Show yourself you rotting daemon.
Found It
ZeroWater filter after about a months use, makes water when heated that smells like bad fish
Bummer - this filter had such good ratings
@Mathias how often does it suggest you change the filters?
@redenigma It depends on your water. It comes with an electronic dissolved solids tester which is nice.
It took mine from 280 PPM tap to 0 PPM which is great.
I would expect it to not work as well over time. But the smell after 1 month is unacceptable.
Others have reported the same thing.
Lesson learned. Research more.
@Mathias I have one that's on my faucet and it specifies that one should not let hot water flow through it, only cold. I don't know if yours is faucet mount or pitcher type, or other, but if hot water was loaded into it, that might have caused trouble (dissolved some interior adhesive or something?)