Grass Valley City Hall is open for business, four days a week. The change to four days is a temporary trial, and runs through the end of the year, when it will be reevaluated. It’s been in effect since Monday. “We’ll do this as a test until the end of December and see how the public views this,” Mayor Ben Aguilar said. City Hall operations now run from 7:30 a.m. to 5:30 p.m. Monday through Thursday, and will be closed to the public on Fridays. “We reached out through the city’s website and included a message on our phone system,” said City Manager Tim Kizer.