"Eia no" literally translates to "Here it is," but in this context, it's a polite and respectful acknowledgment, similar to saying "You too" or "And to you as well."
Here are some other ways to reply to "Malama pono":
* "Malama pono ʻoe" - This means "Take care of yourself."
* "Mahalo" - This means "Thank you," and can be used as a general reply to any kind of greeting.
* "A hui hou" - This means "Until we meet again," and is a common way to say goodbye.
The best reply will depend on the situation and your relationship with the person you are speaking to.