The main ingredients are almost the same, mainly because different brands use different amounts of surfactants. Surfactants often have many functions, such as wetting, penetration, emulsification, dispersion, dissolution-assisting, decontamination, foaming and so on. Black water refill, if bought in a regular business, should be no problem. I'm afraid it's bought in an informal business, and the price is very low. I don't rule out the possibility of fraud.