For divers, caring for the ocean is not only about what happens underwater. It also shows up in our topside habits, from what we pack in the truck, to what we carry onto the boat, to what we reach for every day between dives. One of the simplest of those choices is also one of the easiest to repeat: bringing a reusable bottle instead of buying another single-use plastic one.  That's why reusable bottles have a firm place in...