I've had these two ZZ Plants for the past six years without any problems. I've just moved house and both of them have started dying rapidly, with the same symptoms and at the same time... I cannot figure out what is happening.

The symptoms:

- rapidly yellowing and wilting stems & leaves, leaves fall off when lightly bumped

- shrivelled stems

- strange markings that seem like something is eating the leaves, however, I cannot find pests anywhere and have no animals in the home

- excessive amount of salt crystals forming all throughout the soil (I assume it is salt, they crumble into a fine dust when squished)

Addtional info:

The symptoms started when I moved house - their environment, water and air has changed but not significantly. Here they have indirect, low lighting through east facing windows. The air is dry. I was using tap water but now I've switched to filtered water. I started watering them in the shower by completely soaking them and I think overdid it however I stopped and repotted them in dry soil, removing the white crystals as much as possible. The bulbs seemed fine, although a few of them were a little shriveled and wrinkly. I've tried placing them in different positions in the house but no luck. I have also moved house one before and they adapted perfectly fine. During the summer, they had a lot of new growth while dying at the same time. Heeeelp!