diff --git a/integration/VODE/actual_integrator_simplified_sdc.H b/integration/VODE/actual_integrator_simplified_sdc.H
index 6dedb2c5fc..c2018ccba5 100644
--- a/integration/VODE/actual_integrator_simplified_sdc.H
+++ b/integration/VODE/actual_integrator_simplified_sdc.H
@@ -177,14 +177,14 @@ void actual_integrator (BurnT& state, Real dt)
             std::cout << "temp start = " << std::setprecision(16) << T_in << std::endl;
             std::cout << "rhoe start = " << std::setprecision(16) << rhoe_in << std::endl;
             std::cout << "xn start = ";
-            for (int n = 0; n < NumSpec; ++n) {
-                std::cout << std::setprecision(16) << xn_in[n] << " ";
+            for (auto X : xn_in) {
+                std::cout << std::setprecision(16) << X << " ";
             }
             std::cout << std::endl;
 #ifdef AUX_THERMO
             std::cout << "aux start = ";
-            for (int n = 0; n < NumAux; ++n) {
-                std::cout << std::setprecision(16) << aux_in[n] << " ";
+            for (auto aux : aux_in) {
+                std::cout << std::setprecision(16) << aux << " ";
             }
             std::cout << std::endl;
 #endif
diff --git a/integration/nse_update_simplified_sdc.H b/integration/nse_update_simplified_sdc.H
index 0c74032549..19cdd82ef6 100644
--- a/integration/nse_update_simplified_sdc.H
+++ b/integration/nse_update_simplified_sdc.H
@@ -150,13 +150,13 @@ void sdc_nse_burn(BurnT& state, const Real dt) {
     // the new mass fractions are just those that come from the table
     // make sure they are normalized
     Real sum_X{0.0_rt};
-    for (int n = 0; n < NumSpec; ++n) {
-        X[n] = amrex::max(small_x, amrex::min(1.0_rt, X[n]));
-        sum_X += X[n];
+    for (auto & xn : X) {
+        xn = amrex::max(small_x, amrex::min(1.0_rt, xn));
+        sum_X += xn;
     }
 
-    for (int n = 0; n < NumSpec; ++n) {
-        X[n] /= sum_X;
+    for (auto & xn : X) {
+        xn /= sum_X;
     }
 
     for (int n = 0; n < NumSpec; ++n) {
diff --git a/unit_test/burn_cell_sdc/burn_cell.H b/unit_test/burn_cell_sdc/burn_cell.H
index 1a70dd43c7..4610423ea3 100644
--- a/unit_test/burn_cell_sdc/burn_cell.H
+++ b/unit_test/burn_cell_sdc/burn_cell.H
@@ -334,8 +334,8 @@ void burn_cell_c()
     state_over_time << std::setw(10) << t;
     state_over_time << std::setw(12) << burn_state.rho;
     state_over_time << std::setw(12) << burn_state.T;
-    for (int x = 0; x < NumSpec; ++x){
-        state_over_time << std::setw(12) << burn_state.xn[x];
+    for (auto X : burn_state.xn) {
+        state_over_time << std::setw(12) << X;
     }
     state_over_time << std::endl;