Maybe try getting a Camelbak brand hose insulation. I have no experience with Osprey. Perhaps the Camelbak will insulate better. I don't do a whole lot of cold weather backpacking but I don't have any hose insulation and it usually doesn't freeze solid so long as I keep drinking regularly even below 14. Another trick you could try is to add Gatorade powder to your bladder. It contains sugar and salt which will both lower the freezing point of water some. Also, start the day by putting a couple cups of hot water in the bladder and that will help it last much longer before freezing.