diff --git a/exercises/exercise-fluidsystem/2pproblem.hh b/exercises/exercise-fluidsystem/2pproblem.hh
index 003047c007f3c02b7e82bf858a81e92f95210168..e641611f3c86d95aa7891f9a6b5943ed44f1c342 100644
--- a/exercises/exercise-fluidsystem/2pproblem.hh
+++ b/exercises/exercise-fluidsystem/2pproblem.hh
@@ -160,6 +160,8 @@ public:
 
         // set the depth of the bottom of the reservoir
         depthBOR_ = this->fvGridGeometry().bBoxMax()[dimWorld-1];
+
+        // plot density over pressure of the phase consisting of your component
         if(getParam<bool>("Output.PlotDensity"))
             plotDensity_();
     }