diff --git a/src/grid_mod.F90 b/src/grid_mod.F90
index 42d612c1b7cd957d64be1f4756ec57696629dfdc..9ed9cf02e15c968106d1cfcbb4b4cd7cabc9eb41 100644
--- a/src/grid_mod.F90
+++ b/src/grid_mod.F90
@@ -207,7 +207,7 @@ CONTAINS
     END DO
 
     ! Orszag 2/3 filter
-    two_third_kxmax = 2._dp/3._dp*deltakx*Nkx
+    two_third_kxmax = 2._dp/3._dp*deltakx*(Nkx-1)
     ALLOCATE(AA_x(ikxs:ikxe))
     DO ikx = ikxs,ikxe
       IF ( (kxarray(ikx) .LT. two_third_kxmax) ) THEN
@@ -249,7 +249,7 @@ CONTAINS
     ENDIF
 
     ! Orszag 2/3 filter
-    two_third_kymax = 2._dp/3._dp*deltaky*(Nky/2);
+    two_third_kymax = 2._dp/3._dp*deltaky*(Nky/2-1);
     ALLOCATE(AA_y(ikys:ikye))
     DO iky = ikys,ikye
       IF ( (kyarray(iky) .GT. -two_third_kymax) .AND. (kyarray(iky) .LT. two_third_kymax) ) THEN
diff --git a/src/initial_par_mod.F90 b/src/initial_par_mod.F90
index f0b3a7a1f8195a33357fcddd5d3c85e8e5f8fc76..fefa91183b3087a6c0d8d90bd09f4e4c0238a867 100644
--- a/src/initial_par_mod.F90
+++ b/src/initial_par_mod.F90
@@ -21,12 +21,6 @@ MODULE initial_par
   ! Initialization for random number generator
   INTEGER,  PUBLIC, PROTECTED :: iseed=42
 
-  ! Parameters of initial smooth sine profiles
-  REAL(dp), PUBLIC, PROTECTED ::  init_nb_oscil_density=2._dp ! Number of oscillations
-  REAL(dp), PUBLIC, PROTECTED ::  init_nb_oscil_temp=2._dp
-  REAL(dp), PUBLIC, PROTECTED ::  init_ampli_density=0.1_dp ! Oscillation amplitude
-  REAL(dp), PUBLIC, PROTECTED ::  init_ampli_temp=0.1_dp
-
   CHARACTER(len=128), PUBLIC :: mat_file    ! COSOlver matrix file names
 
   PUBLIC :: initial_outputinputs, initial_readinputs
diff --git a/src/stepon.F90 b/src/stepon.F90
index 2f2d8a7e432c73f309e247caffbcd35f3dc37597..882e1277ccfde6872cdd3f8a413ca48c09b503d5 100644
--- a/src/stepon.F90
+++ b/src/stepon.F90
@@ -39,9 +39,8 @@ SUBROUTINE stepon
       ! Update electrostatic potential phi_n = phi(N_n+1)
       CALL poisson
       ! Update nonlinear term S_n -> S_n+1(phi_n+1,N_n+1)
-      IF ( NON_LIN ) THEN
-        CALL compute_Sapj
-      ENDIF
+      IF ( NON_LIN ) CALL compute_Sapj
+
       !-  Check before next step
       CALL checkfield_all()
       IF( nlend ) EXIT ! exit do loop
@@ -56,7 +55,8 @@ SUBROUTINE stepon
         ! Execution time start
         CALL cpu_time(t0_checkfield)
 
-        IF ( (ikxs .EQ. 1) .AND. (NON_LIN) ) CALL enforce_symetry() ! Enforcing symmetry on kx = 0
+        IF(NON_LIN) CALL anti_aliasing   ! ensure 0 mode for 2/3 rule
+        IF(NON_LIN) CALL enforce_symetry ! Enforcing symmetry on kx = 0
 
         mlend=.FALSE.
         IF(.NOT.nlend) THEN