I got this beautiful peace lily sensation about five weeks ago. I just discovered the yellow leaf and I'd like to troubleshoot this before it gets worse. I suspect it's due to lighting but would appreciate any feedback or tips.
As shown in the photo below, it's placed to the side of a couple large windows which face south. I live in sunny Los Angeles and we are going through a February heat wave - temperatures are in the high 80s and it probably gets to 80-82 inside my home during the day. It seems to get direct sun like it's getting in the picture in the morning for roughly two hours; the rest of the day it's blocked from the sun but still in a bright room.
There were a couple times when I watered once when its leaves drooped. I know that's not healthy so I know I need to get it water before that happens. I'm also a bottom water-er, but will water from the top every so often to make sure nutrients are going through. I allow tap water to sit out overnight so that chlorine can evaporate out before giving it to the plant. I have a humidifier, though it's at the opposite corner of the room, that I run almost every night and if the central air/heat is on.