member key assignment not properly explained, or incorrect assumption/s
"Add Key Assignment" has Serial and Slot fields that are not adequately explained. Eg, I have a RFID card with a unique ID inside, I presume I put that in the "Serial" column ( it's not a serial number, it's a randdom hexadecimal string) . Secondly. I have no idea at all what a "Slot" is. Just guessing ,but is it something like a "zone" in an alarm system?
I suggest adding help text to all the input fields on all the pages to describe what they do, and if that's too hard, then put a 'help' link next to each that goes to a wiki or something with the right information in it.
In many RFID systems, there's a limited number of discrete memory locations which can hold authorized keys. These are usually called slots. This doesn't fix seltzer, but it might help clarify the instant situation.