We recently had our first visit to Kalahari Waterpark and are able to comment and contrast to Aquatopia.
I have an adventurous 8 year old over 48" and a tentative 5 year old who is 43" tall. Good thing about Kalahari is that even if you are not staying at the resort, you can purchase tickets ahead of time. $129.99 for an all day pass or $97.99 after 5pm. It is by far the most expensive but also is the largest indoor waterpark with an amazing amount of rides, hot tubs and arcade games. The challenge I had as a one-parent for the day was with my child under 48". Compared to Aquatopia is was much more challenging at Kalahari to find dual rides for my shorter child. If your kids are all over 48" Kalahari is great for the whole day, if you have little ones between 42"-48" and are solo, we suggest Aquatopia.
We have been to Aquatopia twice now and love it for our kids. It is $59 for a day pass, but you have to book ahead of time as they are very limited with their day passes. If you have a group of 10 or more call ahead to reserve a group reservation for a discount and you can enter the park when it opens at 10am compared to 12 noon for day passes. You may also show up the morning of to check out, but make sure one person is there before opening to ensure you get tickets for the day. Weekdays are more available than weekends. There are a large number of co-rides for your under 48" child. We find Aquatopia to be the best value and has exhilarating rides for all ages.
Our Kalahari Adventure