I live in Tuen Mun , but usually I go to Tai Po Centre to 做負離子 because the staff are very good and not very expensive.The price for 負離子 is around $450,usually can last for almost 1 year.And the staff there told me that 游離子焗油 is worse than 負離子 and can't last for a long time.After 做負離子, my hair become 冇咁乾同滑 and I don't need to do any more treatment to keep it.Just use the shampoo and conditioner is ok. :-P