(section: 2 / paragraph: a / sub-paragraph: vi / line: 1)
As long as the conductivity meter is operated by a 9 volt battery, it is allowed.
(section: 3 / line: 1)
It will be up to the event supervisors. The rules state that event supervisors must notify the students at the beginning of the competition if refills will be allowed or not. Since materials vary widely in density, there is no minimum or maximum number of grams to provide to the students.