Handy Tip: (hint hint campers and boaters)
Make your own ice blocks. Save a 1 gallon milk jug. Clean and fill with water about 7/8 of the way for ice expansion. Place in freezer. Once frozen you can cut open the plastic if you need or just leave it in the container.
1 trick to make it double duty is this. Use a clean spring water jug. Fill 7/8 with good drinkable water. Once frozen toss it in your cooler. As the camping trip progresses and the block melts, it turns into your last gallon of water. Double duty double pleasure!
Over and out.