STOCKTON — The Stockton Fire Department tested some of its firefighters with their underwater during Dive Team Tryouts held Sunday at Chris Kjeldsen Pool in Stockton.Participants were tested in four exercises: a 500-yard swim, 15 minutes treading water, 800 yards snorkel swim, and a 100-yard inert rescue tow. All the events are timed and points awarded for completion times.Dive teams are used for any water rescue or searches after accidents in rivers or lakes.