diff --git a/Software/ChainLube/src/lubeapp.cpp b/Software/ChainLube/src/lubeapp.cpp
index 65afa40..4a1d454 100644
--- a/Software/ChainLube/src/lubeapp.cpp
+++ b/Software/ChainLube/src/lubeapp.cpp
@@ -79,5 +79,8 @@ void RunLubeApp(volatile uint32_t *wheelPulseCounter)
 void LubePulse()
 {
     lubePulseTimestamp = millis() + LUBE_PULSE_LENGHT_MS;
-    LubeConfig.tankRemain_µl = LubeConfig.tankRemain_µl - LubeConfig.amountPerDose_µl;
+    if (PersistenceData.tankRemain_µl < LubeConfig.amountPerDose_µl)
+        PersistenceData.tankRemain_µl = 0;
+    else
+        PersistenceData.tankRemain_µl = PersistenceData.tankRemain_µl - LubeConfig.amountPerDose_µl;
 }
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