diff --git a/fluidsim/solvers/ns2d/strat/output/spect_energy_budget.py b/fluidsim/solvers/ns2d/strat/output/spect_energy_budget.py
index ed90e0dc5ee3c6388f13dbe4963f77c77ba4c89f_Zmx1aWRzaW0vc29sdmVycy9uczJkL3N0cmF0L291dHB1dC9zcGVjdF9lbmVyZ3lfYnVkZ2V0LnB5..346a5c52433783087a5eda15c862d9ead1003fc7_Zmx1aWRzaW0vc29sdmVycy9uczJkL3N0cmF0L291dHB1dC9zcGVjdF9lbmVyZ3lfYnVkZ2V0LnB5 100644
--- a/fluidsim/solvers/ns2d/strat/output/spect_energy_budget.py
+++ b/fluidsim/solvers/ns2d/strat/output/spect_energy_budget.py
@@ -220,6 +220,9 @@
             dset_dissEK_ky = f["dissEK_ky"].value
             dset_dissEA_ky = f["dissEA_ky"].value
 
+        if tmin is None:
+            tmin = 0
+
         if tmax is None:
             tmax = np.max(times)
 
diff --git a/fluidsim/solvers/ns2d/strat/output/spectra.py b/fluidsim/solvers/ns2d/strat/output/spectra.py
index ed90e0dc5ee3c6388f13dbe4963f77c77ba4c89f_Zmx1aWRzaW0vc29sdmVycy9uczJkL3N0cmF0L291dHB1dC9zcGVjdHJhLnB5..346a5c52433783087a5eda15c862d9ead1003fc7_Zmx1aWRzaW0vc29sdmVycy9uczJkL3N0cmF0L291dHB1dC9zcGVjdHJhLnB5 100644
--- a/fluidsim/solvers/ns2d/strat/output/spectra.py
+++ b/fluidsim/solvers/ns2d/strat/output/spectra.py
@@ -112,6 +112,8 @@
             kx = dset_kxE.value
             ky = dset_kyE.value
 
+            if tmin is None:
+                tmin = 0
             if tmax is None:
                 tmax = np.max(times)