That age group might be a little on the old side. I think kids 5-9 are ideal. Older kids will get bored, or end up spending a lot of time/money at the arcade.
As indoor water parks go, it is fairly standard (almost identical to cocokeys)
I took 2 kids, 5&7 there last year. they had a great time but after a 3 or 4 hours they were basically exhausted. maybe the older kids will have better stamina but with limited options for rides they will get bored before they get tired.