C.W.
I prefer Hawaiian Falls. There is also Bad Konigshofen at Stoval Park in Arlington off of Sublett. It's a city park, but it has areas for kids of all ages. From fountains, to a shallow arrow with the stuff to squirt with, and to another area for the kids to swim and dive, and a few slides. It cost very little to get in, and you are allowed to bring coolers, and might be more cost prohibitive to everyone.