New question about humidity

[chickenlisa]

Thanks-I'm wondering about maybe adding food coloring to the water that I add,then I could see it better. Is there any harm from doing that? Anyone know if the food coloring would evaporate too? I just want the H2O to evaporate and leave the color in the water trough then I could add more H2O. But I'm just not seeing the water down there under the turner, not the troughs.
Lisa