Fluid.NULL is identical to Block.AIR

src/net/torvald/terrarum/blockproperties/Fluid.kt

@@ -8,7 +8,7 @@ import net.torvald.terrarum.gameitems.ItemID
  */
 object Fluid {
 
-    val NULL = "fluid@basegame:0"
+    val NULL = Block.AIR
     val WATER = "fluid@basegame:1"
     val LAVA = "fluid@basegame:2"
 

src/net/torvald/terrarum/blockproperties/FluidCodex.kt

@@ -33,6 +33,9 @@ class FluidCodex {
         }
     }
 
+    fun getOrNull(blockID: ItemID?): FluidProp? {
+        return fluidProps[blockID]
+    }
 
     /**
      * Later entry (possible from other modules) will replace older ones