Be sure to spare one day to visit this waterpark when you are in jakarta. The area is not huge but it has all the attractions needed to make it worth the visit. Dont miss the Hairpin, one of slides where you could fit 4 people onto one tube, whole lotta fun! There are plenty of food stalls in the food court area, spacious locker room area and showers. Be sure to try the sate ayam (chicken satay), at rp 35k or USD 4.2 per portion it is a bargain.
The only downside is you have to pay for everything from towels (byo if you have it) to lockers (Rp 25k for singles and Rp 50k for family sized).
They have photographers on the slides. You could choose the pics on the way out and pay Rp 25k per photos if you decide to buy it.