only water will freeze in this water we're having right now, lol
my mixture is2 parts boiled water cooled down (which is more or less like deionised water) and1 part concentrate washer fluid of your choice (i got a big bottle from Halfords which is green instead of blue
), and 1 part of RainX washer additive.
At least Kia's are not fussy about what fluids they use. My old Ibiza used to be a fine art of getting the most out of the fan type sprayers and not freezing up and popping out the washer pipes!