I don't understand the point of blowing out the lines and then putting pink stuff in. Blowing the lines out is a waste of time and effort if you're using antifreeze. Just bypass the water heater and drain it and start pumping antifreeze into the system. Get all the taps and faucets to run undiluted pink and then dump some in the drains and you're done. There's absolutely no need to blow the lines out beforehand.
I live where it gets down to -30 celsius a few times each winter and the above method has always worked.