You could try Little Splashes Swim School, which has a non-chlorinated heated pool with purified water. It's located in Bedok. http://littlesplashes.com.sg/
Currently my daughter is enrolled in AquaBambinos in Serangoon. Little splashes was also shortlisted by us but decided on the former due to living distance.
Hi, you can take a look at www.oyougu.com We have a team of certified coaches for your requirement for swimming lesson.
thanks
Lishi Qiu