Taobao has almost everything, and things have gotten a lot better since 2009 when I first created this post! However, the quality and reliability of the sellers and equipment is still a bit of a lucky draw. Having lived here for so long, I have some good sources or can custom make things myself, so if anybody is interested or needs some help building hydroponics systems in China, then PM me.
@pengyou: It's good to see another hydroponics enthusiast on the mainland! If you are ever in Shanghai, let me know and I can show you the hydroponics systems I am running. I am currently doing about 2.4 sqm of completely enclosed and isolated systems, testing the growing results between a 220w X2-style
led grow light against a 600w HID air cooled reflector, using a top drip automated irrigation system and Canadian imported
nutrient solution by Advanced
nutrients.