Orange seedling leaf worry

[citruslover]

Hi!

I am growing seven healthy orange seedlings in well-drained containers. They look healthy overall and are enjoying the sun.
I am being very careful not to over-water. There’s a white salt-like deposit on the leaves though. Does anyone have any idea what it might be, and what I should do about it?

Looking forward to all your suggestions!

-Citrus Lover

 

[Chuck]

If it rubs off and your water is hard it is probably water scale deposits

 

[citruslover]

If it rubs off and your water is hard it is probably water scale deposits

Thank you. It does not rub off. I use the same water for other plants and their leaves seem okay.