diff --git a/bfps/DNS.py b/bfps/DNS.py
index 6f46fb21169c4fdeff2c09354cb3803b724f71fd..5e250bd358a1c0c4ce32d3d163006b3c977d156e 100644
--- a/bfps/DNS.py
+++ b/bfps/DNS.py
@@ -691,6 +691,8 @@ class DNS(_code):
             opt.fk1 = self.parameters['fk1']
         if type(opt.injection_rate) == type(None):
             opt.injection_rate = self.parameters['injection_rate']
+        if type(opt.dealias_type) == type(None):
+            opt.fk1 = self.parameters['dealias_type']
         self.parameters['nu'] = (opt.kMeta * 2 / opt.n)**(4./3)
         if opt.forcing_type == 'linear':
             # custom famplitude for 288 and 576
@@ -698,20 +700,17 @@ class DNS(_code):
                 self.parameters['famplitude'] = 0.45
             elif opt.n == 576:
                 self.parameters['famplitude'] = 0.47
+        kM = opt.n * 0.5
+        if opt.dealias_type == 1:
+            kM *= 0.8
         elif opt.forcing_type == 'fixed_energy_injection_rate':
-            kM = opt.n * 0.5
-            if self.parameters['dealias_type'] == 1:
-                kM *= 0.8
             # use the fact that mean dissipation rate is equal to injection rate
             self.parameters['nu'] = (
-                    self.parameters['injection_rate'] *
+                    opt.injection_rate *
                     (opt.kMeta / kM)**4)**(1./3)
         elif opt.forcing_type == 'fixed_energy':
-            kM = opt.n * 0.5
-            if self.parameters['dealias_type'] == 1:
-                kM *= 0.8
-            kf = 1. / (1./self.parameters['fk0'] +
-                       1./self.parameters['fk1'])
+            kf = 1. / (1./opt.fk0 +
+                       1./opt.fk1)
             self.parameters['nu'] = (
                     (opt.kMeta / kM)**(4./3) *
                     (np.pi / kf)**(1./3) *