diff --git a/src/configs/reactor.json b/src/configs/reactor.json
index 879a4cf..10b9bb1 100644
--- a/src/configs/reactor.json
+++ b/src/configs/reactor.json
@@ -136,12 +136,12 @@
         }
       },
       "timeStep": {
-        "default": 0.001,
+        "default": 1,
         "rules": {
           "type": "number",
-          "min": 0.0001,
-          "unit": "h",
-          "description": "Integration time step for the reactor model."
+          "min": 0.001,
+          "unit": "s",
+          "description": "Integration time step in seconds. The kinetics engine converts to days internally (timeStep / 86400) before each ASM Euler step; the HTML editor labels this field [s] and tests assume seconds. Do not change the unit without updating baseEngine.js line 40 in the reactor submodule."
         }
       }
     },