Complete "Consistent proportions of WATR and SALT in SLTW" after REALISTIC revert

src/simulation/Simulation.cpp

@@ -3695,7 +3695,7 @@ void Simulation::update_particles_i(int start, int inc)
 								s = 0;
 							}
 #else
-							if (1>rand()%6) t = PT_SALT;
+							if (rand()%4==0) t = PT_SALT;
 							else t = PT_WTRV;
 #endif
 						}