diff --git a/code/modules/atmospherics/machinery/components/unary_devices/tank.dm b/code/modules/atmospherics/machinery/components/unary_devices/tank.dm
index e96ccdb25b..d6c18b1beb 100644
--- a/code/modules/atmospherics/machinery/components/unary_devices/tank.dm
+++ b/code/modules/atmospherics/machinery/components/unary_devices/tank.dm
@@ -21,7 +21,7 @@
 	air_contents.set_volume(volume)
 	air_contents.set_temperature(T20C)
 	if(gas_type)
-		air_contents.set_moles(AIR_CONTENTS)
+		air_contents.set_moles(gas_type, AIR_CONTENTS)
 		name = "[name] ([GLOB.meta_gas_names[gas_type]])"
 	setPipingLayer(piping_layer)
 
@@ -32,8 +32,8 @@
 /obj/machinery/atmospherics/components/unary/tank/air/New()
 	..()
 	var/datum/gas_mixture/air_contents = airs[1]
-	air_contents.set_moles(/datum/gas/oxygen, AIR_CONTENTS * 0.2)
-	air_contents.set_moles(/datum/gas/nitrogen, AIR_CONTENTS * 0.8)
+	air_contents.set_moles(/datum/gas/oxygen, AIR_CONTENTS * 0.21)
+	air_contents.set_moles(/datum/gas/nitrogen, AIR_CONTENTS * 0.79)
 
 /obj/machinery/atmospherics/components/unary/tank/carbon_dioxide
 	gas_type = /datum/gas/carbon_dioxide