Q.Christmas cactus leaves are changing color.
My christmas cactus has been doing good since I moved in to my place back in 2016(it came with the house) it really livened up when we put it in the livingroom. But i have noticed in th4 last month or so that the leaves look a little more lighter or even have a grey tint to them like they have dust on them, But they arnt dusty. The leaves where thick tough and deep green a couple months back. Is this a bad sign? Someone told me 5o put rusty nails in the dirt to darken the color, but I’m not sure if that’s the issue. I’ll attach photos.
The lighter leaf color can be due to lack of light.
From the photo I can't see the dusty leaves, but from your description it sounds like powdery mildew. This is not a fungus ofter found on indoor Christmas Cactus, but it can happen. Air flow around the plant can help.