I ordered a new NVR from Andy. I am trying to calculate how much hard drive space I will need to keep 30 days worth of recordings. Currently cameras are in a parking garage recording a 30 second clip from 13 1080p camera's motion. It is not a high traffic parking garage but there is a bank attached. Normal traffic is from 9a-5p Mon-Fri. I dont want to end up with too much unused space. any guesses?