diff --git a/src/potential_file_reader.cpp b/src/potential_file_reader.cpp
index a8aa0adb43..379a2ba2fc 100644
--- a/src/potential_file_reader.cpp
+++ b/src/potential_file_reader.cpp
@@ -34,10 +34,10 @@ PotentialFileReader::PotentialFileReader(LAMMPS *lmp,
   Pointers(lmp),
   reader(nullptr),
   filename(filename),
-  potential_name(potential_name)
+  filetype(potential_name + " potential")
 {
   if (comm->me != 0) {
-    error->one(FLERR, "PotentialFileReader should only be called by proc 0!");
+    error->one(FLERR, "FileReader should only be called by proc 0!");
   }
 
   try {
@@ -112,7 +112,7 @@ TextFileReader * PotentialFileReader::open_potential(const std::string& path) {
     utils::logmesg(lmp, fmt::format("Reading potential file {} with DATE: {}", filename, date));
   }
 
-  return new TextFileReader(filepath, potential_name + " potential");
+  return new TextFileReader(filepath, filetype);
 }
 
 /* ----------------------------------------------------------------------
@@ -121,7 +121,7 @@ TextFileReader * PotentialFileReader::open_potential(const std::string& path) {
 ------------------------------------------------------------------------- */
 
 std::string PotentialFileReader::get_potential_date(const std::string & path) {
-  TextFileReader reader(path, potential_name + " potential");
+  TextFileReader reader(path, filetype);
   reader.ignore_comments = false;
   char * line = nullptr;
 
diff --git a/src/potential_file_reader.h b/src/potential_file_reader.h
index 0d3d52acfe..d2861c0a18 100644
--- a/src/potential_file_reader.h
+++ b/src/potential_file_reader.h
@@ -26,19 +26,20 @@
 namespace LAMMPS_NS
 {
   class PotentialFileReader : protected Pointers {
+  protected:
     TextFileReader * reader;
     std::string filename;
-    std::string potential_name;
+    std::string filetype;
 
     TextFileReader * open_potential(const std::string& path);
     std::string get_potential_date(const std::string & path);
 
   public:
     PotentialFileReader(class LAMMPS *lmp, const std::string &filename, const std::string &potential_name);
-    ~PotentialFileReader();
+    virtual ~PotentialFileReader();
 
     void skip_line();
-    char * next_line(int nparams);
+    char * next_line(int nparams = 0);
     void next_dvector(int n, double * list);
   };