Buy on the dip. A similar fall also happened in the past for bitcoin due to China. But the price hit floor and surged about 1/2 year later. Looks like bitcoin bounced of $4100. $4000 seems to be support, which also is the cost of electricity at 12/31/2017. Cost of electricity is $2500 now. Add $1000 average cost of a mining machine, and floor is $3500.