Smoke from Exhaust

[AlvinSimonTheodore]

Did a coolant flush a few days ago and a massive white smoke cloud came from the exhaust while I was bleeding the system, lasted about 30 seconds. Been driving around since and absolutely no smoke now, no overheating at idle or driving, no puddles under the car. Oil looks fine, no milky colour. Filled coolant to 'full' line when the engine was cold and have noticed it has slightly dropped, unsure if this is just due to air being bleeding while I drove it. Prior to the flush, absolutely no white smoke coming from tail pipe and coolant was full, only changed because it was due. Completely at a loss, any ideas? 

[AlvinSimonTheodore]

To clarify, coolant level has dropped about 0.5 cm tops from when it was filled.