diff --git a/mote/v2/openwrt/package/flukso/luasrc/flukso/data.lua b/mote/v2/openwrt/package/flukso/luasrc/flukso/data.lua
index b01d723..bec8dc5 100644
--- a/mote/v2/openwrt/package/flukso/luasrc/flukso/data.lua
+++ b/mote/v2/openwrt/package/flukso/luasrc/flukso/data.lua
@@ -113,19 +113,32 @@ function polish(M, now, cutoff)
 	end
 end
 
-function json_encode(M)
+function json_encode(M, entries)
 	local J = {}
 
+	if entries then
+		arr_size = 5*entries + 2
+	else
+		arr_size = 0
+	end
+
 	for sensor, T in pairs(M) do
 		local H = timestamps(T)
-		local SB = {'['} -- use a string buffer for building up the JSON string
+
+		local SB = table.create(arr_size, 0)                                              
+		SB[1] = '[' -- use a string buffer for building up the JSON string           
 
 		for k, timestamp in ipairs(H) do
-			SB[#SB+1] = '[' .. timestamp .. ',' .. T[timestamp]  .. '],'
+			SB[#SB+1] = '['
+			SB[#SB+1] = timestamp
+			SB[#SB+1] = ','
+			SB[#SB+1] = T[timestamp]
+			SB[#SB+1] = '],'
 		end
 
 		SB[#SB] = SB[#SB]:sub(1, -2) -- remove the trailing comma from the last entry
 		SB[#SB+1] = ']'
+
 		J[sensor] = table.concat(SB)
 	end
 
diff --git a/mote/v2/openwrt/package/flukso/luasrc/fluksod.lua b/mote/v2/openwrt/package/flukso/luasrc/fluksod.lua
index ffa1dcc..c524db9 100755
--- a/mote/v2/openwrt/package/flukso/luasrc/fluksod.lua
+++ b/mote/v2/openwrt/package/flukso/luasrc/fluksod.lua
@@ -321,7 +321,7 @@ function publish(child)
 
 		while true do
 			measurements:polish(os.time(), LAN_POLISH_CUTOFF)
-			local measurements_json = measurements:json_encode()
+			local measurements_json = measurements:json_encode(LAN_POLISH_CUTOFF)
 
 			for sensor_id, json in pairs(measurements_json) do
 				local file = LAN_PUBLISH_PATH .. '/' .. sensor_id