First use of the Aeris xr-1 computer. First two dives (day1) at 15ft the safety stop countdown activated correctly. Third & fourth dives (day 2) the countdown did not activate at all. I waited at 15ft to see if it would, also toggled through the other dive-mode screens-- nothing. I did change some settings at the end of the first day. Did I do something to deactivate that feature? 
