diff --git a/README.md b/README.md
index d08160c..e4450cd 100644
--- a/README.md
+++ b/README.md
@@ -107,7 +107,7 @@ Note: We supply two PCL filters within STVL to massage the data to lower compute
 rgbd_obstacle_layer:
   enabled:               true
   voxel_decay:           20     #seconds if linear, e^n if exponential
-  decay_model:           0      #0=linear, 1=exponential, -1=persistent
+  decay_model:           0      #0=linear, 1=exponential, 2=persistent
   voxel_size:            0.05   #meters
   track_unknown_space:   true   #default space is unknown
   observation_persistence: 0.0  #seconds
diff --git a/spatio_temporal_voxel_layer/src/spatio_temporal_voxel_grid.cpp b/spatio_temporal_voxel_layer/src/spatio_temporal_voxel_grid.cpp
index e5858c9..ceb83a7 100644
--- a/spatio_temporal_voxel_layer/src/spatio_temporal_voxel_grid.cpp
+++ b/spatio_temporal_voxel_layer/src/spatio_temporal_voxel_grid.cpp
@@ -348,7 +348,7 @@ double SpatioTemporalVoxelGrid::GetTemporalClearingDuration(
   } else if (_decay_model == 1) {  // Exponential
     return _voxel_decay * std::exp(-time_delta);
   }
-  return _voxel_decay;  // PERSISTENT
+  return std::numeric_limits<double>::max();  // PERSISTENT
 }
 
 /*****************************************************************************/