Long-time favorite out in Hongqiao right here. On the weekends it's usually packed with a rowdy, often boozed up laowai crowd drinking beers and listening to EDM on cheap speakers. During the week, it's a haven for hungover DJs and underemployed English tutors. They're open from early June to the end of September, daily, from 9am to 7pm. Fee is 130rmb/person a 6rmb for an on-site health check. No swimming cap rule, thankfully. Definitely hard to get a seat on the weekend.