you can use a Camelbak, and I have, but that was a very long 3hr dive at very shallow depths. I would say that as a recreational diver where your long dives will only be 60-75 minutes at low exertion levels, if you start hydrated and drink between dives, its not worth the effort to bother. Just don't get lulled into thinking that your not thirsty, you'll realize your thirsty on your second dive when you legs cramp terribly.
remember, cold water (yes 80F is cold compared to your warm 98F blood) will induce your body to pee, so if you don't have the urge to pee half way through the dive, your probably dehydrated.