diff --git a/powerwall.sh b/powerwall.sh
index 3c5319eb..957e28b2 100755
--- a/powerwall.sh
+++ b/powerwall.sh
@@ -97,8 +97,8 @@ CHECKTEMP_SERVICE(){
 				echo ${TEMP_THRESHOLDS[${SENSOR}]} | cut -d',' -f 2 | read temp_crit
 				echo ${TEMP_THRESHOLDS[${SENSOR}]} | cut -d',' -f 3 | read temp_crit_sys
 			
-				if [ "${last_temp[${SENSOR}]}" != ""]; then
-					temp_diff=$((${last_temp[${SENSOR}]%.*} - ${temp_f%.*}))
+				if [ "${last_temp[${SENSOR}]}" != "" ]; then
+					temp_diff=`expr ${last_temp[${SENSOR}]%.*} - ${temp_f%.*}`
 					[ $temp_diff -lt 0 ] && temp_diff=$(($temp_diff * -1))
 				else
 					last_temp[${SENSOR}]=0
@@ -149,8 +149,11 @@ Shutting down system servers!!" 1
 					errtime=$(expr `date +%s` - $(stat -c %Y ${logtemp}))
 					[ $errtime -ge 3600 ] && echo "($datetime) - ${SENSOR} - ${temp_f}F - Normal Temp" >> ${logtemp}
 				fi
-			
-				QRY="USE servermonitor; INSERT INTO sensor_data (\`sensorid\`, \`date\`, \`temp\`, \`hum\`) VALUES ('${SENSOR_ID[${SENSOR}]}','${datetime}','${temp_f}','${temp_h}')"
+				if [ "${temp_h}" != "" ]; then
+					QRY="USE servermonitor; INSERT INTO sensor_data (\`sensorid\`, \`date\`, \`temp\`, \`hum\`) VALUES ('${SENSOR_ID[${SENSOR}]}','${datetime}','${temp_f}','${temp_h}')"
+				else
+					QRY="USE servermonitor; INSERT INTO sensor_data (\`sensorid\`, \`date\`, \`temp\`) VALUES ('${SENSOR_ID[${SENSOR}]}','${datetime}','${temp_f}')"
+				fi
 				${mysql_conn} -e "${QRY}"
 			else
 				SENDNOTICE "${SENSOR} ERROR" "($datetime) ERROR reading temperature" 1