I don't think tubes are allowed in the wave pools. We went in the spring shortly after it opened and we could not take tubes in, so we ended up helping our dd12 so she could go farther out.
I would recommend an entire day for Aquatica. I would also HIGHLY recommend renting a cabana. I know they are pricey, but soooo worth it. We absolutely loved ours and think every waterpark should have them. We ordered lunch from the cabana, had it delivered and it was wonderful. Our kids loved it. We even ordered a couple extra items off the menu, like fresh fruit salad, so we had a snack for later.
When we go back to Orlando in a couple years, my dh said the first thing we are doing is Aquatica, no exceptions!
Oh, yeah, sunscreen, sunscreen and more sunscreen. . . burned kids are NO FUN!!