diff --git a/spades.wdl b/spades.wdl
index 408ea087f2899dc5b488b0fca4d05ef4cac8b0d9..49c095c8e7ef165a4e1e2b191f61f984f980f6ca 100644
--- a/spades.wdl
+++ b/spades.wdl
@@ -22,8 +22,8 @@ task spades {
     Boolean? disableGzipOutput
     Boolean? disableRepeatResolution
     File? dataset
-    Int? threads = 1
-    Int? memoryGb = 4
+    Int threads
+    Int memoryGb
     File? tmpDir
     String? k
     Float? covCutoff
@@ -73,7 +73,7 @@ task spades {
         File log = outputDir + "/spades.log"
     }
     runtime {
-        cpu: select_first([threads])
-        memory: select_first([memoryGb])
+        cpu: threads
+        memory: memoryGb
     }
 }
\ No newline at end of file
diff --git a/unicycler.wdl b/unicycler.wdl
index e9da2972204810d01a90cecd747aeb49f78e5f3b..ff3d2b5d0c9314849215aadc41fd489c74927067 100644
--- a/unicycler.wdl
+++ b/unicycler.wdl
@@ -4,13 +4,13 @@ task unicycler {
     File short2
     File? unpaired
     File? long
-    String out
+    String out,
     Int? verbosity
     Int? minFastaLength
     Int? keep
     Boolean? vcf
-    Int? threads = 1
-    Int? memory = 4
+    Int threads
+    Int memory
     String? mode
     Float? minBridgeQual
     Int? linearSeqs
@@ -90,7 +90,7 @@ task unicycler {
     }
 
     runtime {
-        cpu: select_first([threads])
-        memory: select_first([memory])
+        cpu: threads
+        memory: memory
     }
 }
\ No newline at end of file