Hi robin98(NZ(9b)) thanks for your help! *I've had the plants for approximately 2 years. *I repotted them approximately 1-2 months ago. *Both were in terracotta pots, now just the larger one is. The smaller one is in a plastic pot now, there's been no change in either plant other than getting worse. *I water both when the top 2 inches are dry, I use my finger or a wood dowel to tell if the soil is damp, mainly my finger. If the top 2 inches are dry I water until soaked, with the water draining freely through the holes. I never let them sit in water for longer than maybe 30mins, after watering. *The build up was before I repotted, it looks like salt or water hardness. I removed them from those pots and placed them in fresh pots that had been disinfected prior to use. There's some build up since that time on the rim of the terracotta pot (can be seen slightly in photo below of the top of the pot) I'm still sad, but learning to cope with it! ;) Well, I'm trying to learn from this experience. Thank-you so much! I've included some newer photos, please feel free to ask more questions if necessary. I'm considering removing the large one from it's pot, to repot again, but into a smaller pot after I remove some roots. It smells from the top of the soil now, and although when I repotted previously there was no indication of rot I'm thinking this is either leaf disease of some type or root rot. I removed these leaves: Then this started: Here's a picture of the top of the pot: Thanks everyone in advance! Let's hope we can save these guys!

Monsteras are semi-epiphytic in that they start off on the ground and then climb up trees. The roots run along the tree trunks exposed to a lot of air and breezes. On the ground most of the roots run through the leaf litter which is usually light and airy. Rain and air humidity is high but water run off is virtually instantaneous. You're better off using a very light epiphytic medium that drains fast and water more frequently.

You don't have to water them in the shower LOL. I mean if it is convenient to do so it is fine, but you have to lug the plants into the shower, soak them well and then let them dry off so they don't drip all over your floors. I just pour water onto the soil surface when needed......wetting the entire surface and until it starts to drain through. How often will depend on conditions (humidity, temperature, how root bound the plant is, how big the plant is, etc.). I generally try to water in the morning so any excess is gone before evening....probably not as important for the Monstera but good practice with some succulents and plants that could rot easily if water sits on the stems too long. An occasional shower, or placed outside in a gentle warm rain, will keep dust off the broad leaves.

Yours is slightly larger than mine. Mine is my first and I got it at a nursery in early June. I really like it. To me, the marks on your leaves look like shipping damage from the leaves being bent too much. The younger leaves yellowing could be just from acclimation to your new environment. The leaves pulling out and the new leaves that appear to fall apart - I am not sure what that could be. It probably all began with the lack of drainage you mentioned. Fungus gnats love moist unventilated indoor soil. I used to have a lot inside in the winter and none now in the summer. Others on this board can give you some more help than me. I've had a few indoor plants that began dying in early Spring. Then when I placed them outdoors and in the ground they ALL perked up. My banana had several treatments of copper fungicide even after being planted in the ground. It's beginning to look nice. Back to my M. Deliciosa - I place it outdoors almost daily in dappled sun and never in the wind. It's doing well. No issues. I bring it in when windy or if rain is eminent. I also back off the water. I only water when I can detect dryness by sticking my finger 1" into the soil. It's hard for me to not water like I do other plants. But I know they have aerial roots in their natural habitat and climb up trees. So their roots are exposed to the air. Here's mine when I got it on June 10: https://st.hzcdn.com/simgs/48e2ed860b1dde23_9-4068/home-design.jpg And here it is outside tonight - 3 new leaves have opened since buying it. It still bothers me to see the soil that dry. Those flipped over chairs around them filter the sun they get: (on left is Philo. 'Brasil, center is Pothos Epipremnum aureum 'Manjula')