You might want to repost this to the "using chlroine and chlorinating chemicals" thread.

This thread is for using Baquacil (and for folks that want to learn how to convert from Baquacil to Chlorine). You'll probably get a lot more responses over on the other thread.

But...I agree with the previous post. Have your friend test their water and post the results. Free chlorine, Combined Chlorine, Alkalinity, and Ph at a minimum.