Have had around a year and it was doing very well until the last month. Humidity levels are consistently around 55-65% . Forced air heating and unfortunately is a little near one area due to being near the window. (Other monsteras near another window/heating vent are doing well). Was sprayed with insecticidal soap early fall when adjacent plants showed aphids. Consistent issue with fungus gnats, been using mosquito dunks and have reduced quite a bit. Soil isn’t how I’d like due to availability of supplies/location right now but did recently repot due to the curling (no yellow) and compaction of the original soil and not drying out (wet concrete-like). Did have trouble with the root system /access for clearing some of the compact soil. I didn’t want to stress it anymore....but perhaps I did the worst thing to do? Now it’s sort of a mix of pro-mix premium and perlite with a few charcoal/bark pieces that had left and was only watered a bit once. Trouble drying out the bottom and suspect too many (fine?) peat that is clumping and not drying out. I have tried to loosen it up a little to help dry out but still damp below the surface. Could this be what is killing it?? Suddenly, it’s going yellow and it’s happening very very fast. Has never had yellowing before nor curling. I have cut off a few dying leaves to have a look at it and with pocket microscope I can see little fine silk threads on leaf here and there and brown rotting dots/looking spots on another leaf. No pests I could see on the leaves except when checking near the base of the stem where it exited the soil, there were microscopic (very clear, no colour-tinge at all little bugs crawling around. I’m not sure what it was but looked like a mite??? ) The questions I have are: 1) Should I take it out of this soil? Do I look at roots? How to look at middle roots? 2) Should I try to get a picture of the clear bug or the silky strand things I can see (with my phone camera through the eyepiece of the pocket scope lol) 3) Is there any way to save this, and it was a fairly large plant for my house and I loved it. The first pic doesn’t look nice and full but it used to be. I’m sad! 4) Likely happening due to stress from watering/heat/humidity/pests? And if it helps any, I did propogate a stem in the fall and it grew a beautiful new leaf. Except the older leaf now is also drooping. (Not the new one).....I feel like a failure at this and wish I knew more on how to *not* ruin them. Many thanks for all your help.