diff --git a/PyCO2SYS/engine/system.py b/PyCO2SYS/engine/system.py
index aea65b66..6c363d4e 100644
--- a/PyCO2SYS/engine/system.py
+++ b/PyCO2SYS/engine/system.py
@@ -28,6 +28,7 @@
     ),
     # Pressure correction factors for equilibrium constants
     # Equilibrium constants at pressure and on the seawater pH scale
+    # Equilibrium constants at pressure and on the requested pH scale (YES, HERE!)
 }
 
 # Define functions for calculations that depend on icase: