Don't Panic !!!!!

There is lots of oxy in the water for that amount of time. It maybe the water change. Did you up the nutes or change your mix in any way ? Did you bring the level of water to the same mark so roots hang in water ? If not I would take a cup os so from the rez and pour over the rootball in the netpot. It will come back quick.

My bro just had one do the same thing but he is still in veg. We are not shure why it did that but a little rez water broght it back quick and is doing fine.

If there were any changes in rez mix then it could be something else. Let us know.

Oh yea I think we figured the fresh rez mix was a bit cold and needed to warm up on these cold days first. So we will check temp of water before change to make shure it's not toooo hot or tooo cold.