Well, I don't like water or beads in my hoops because it throws the weight balance off. If it doesn't bother you, then don't worry about it. Usually the beads are just there to make sound. I actually recently made a hoop for a woman who requested I make it rattle to remind her of childhood hooping as she was letting it whirl. Her kids love it too.
Harder pushes will make a hoop go faster, but with the balance thrown off by the water, it may get wonky. I often play with this type thing when I see hoops in the store. You hoop and it swishes 3 times then all the pebbles get locked in place with force for a spin or two then they start going around again. If you do a fast enough weave, the pebbles will just stay where the outward (centrifugal force) is.
If you enjoy it and it feels good, stick with it. If its difficult or unbalanced feeling, you can try draining the water, but it will still be a very light hoop for you if you are a beginner. My definition of "big enough" for beginners (if thats what you are) is usually 38-40 inches. I haven't found a kiddy hoop that big. They make 36s now fairly regularly in kids hoops, but I still don't like how light and flimsy they are.
Good luck!