That is interesting actually there isn't any extra post processing, single exposure from the original all of the sky is blown out but the blue reflection is certainly there. I was using a polariser to remove the reflection where the stump is so you could see it. and using recovery thats what came up. I would say its the effect of the polariser.
Other than that don't really know! lol Anyone got any ideas?
The second one the polariser was rotated toward the sky and mountains to emphasise the colour and depth as the clear water would be a distraction.