I bought a glass inkwell. It looks nice on my desk, and I thought it can keep some Diamine Oxblood that came in an ugly plastic bottle.

I now realize however that the inkwell does not close airtight, i.e. the lid does not have a seal of some sort. This must affect the ink, and leaves me with questions:

How fast does the water in ink evaporates?
How fast does the UV part of ambient light harm the ink?
When does that negatively influence the ink and/or the pen you ink it with?
Can you dillute ink (with water?) at some point? Or is this to be avoided?

Or should I keep the inkwell for decoration purposes only? Alternatively, I could start writing a very great deal in a very short time...

Thanks in advance for your thoughts.