I have a cider that I just finished up. I let it clear for about two months. It looks, tastes, and smells nice. I went to stabilize it to backsweeten a little by racking onto crushed camden tablets and pottasium sorbate. A few days later I still see some floating pieces of white 'stuff'. I tried to shake it up a little to try and break it up and dissolve it, but to no avail. Any suggestions?