Firefighters are working towards increasing the containment of the Nena Springs Fire in the Warm Springs Reservation, but until moisture arrives over the fire, officials say containment will remain 75%.  Its final footprint is expected to remain 68,135 acres.  Surface fire is smoldering in duff and dead and down logs.  A handcrew is directing a light helicopter over hotspots to provide target drops of water.  The 240 firefighters assigned to the fire are beginning to hit their maximum days of work and will return home to rest before taking new assignments.  As they leave, a smaller force of firefighters will remain at Warm Springs to complete the work left yet to do.  A transfer of command is occurring today to a smaller management organization.