I simply punch one small hole on top and one to two small holes on the bottom of about 7 or 8 bleach bottles and string them across my pool. The bleach slowly leaches out adding chlorine to the pool. Last vacation I came home and have 2ppm free chlorine which is fine with my 30 CYA. Here's a couple pictures.

http://www.jreece.com/bleach1.jpg
http://www.jreece.com/bleach2.jpg