mano I always use salt....Always.....maybe a teaspoon per quart bag. I put about 10 fillets in each quart bag and fill it up until the fillets are submerged. You do not want any out of the water or else they will freezerburn. Usually this is about 3/4 full of water. I then zip it shut and push all air out and in the freezer they go. I do buy good heavy ziploc bags. The cheap ones will tear.