I use it at work for removing chlorine from effluent water that we disinfect with chlorine due to fish pathogens (I work in aquaculture research). I do not recomend you use it because you need to be sure that you add an exact amount to de-chlorinate with (need a fancy test kit like from Hach) otherwise you could have some residual sodium thio left. The MSDS lists it as an irritant (http://www.jtbaker.com/msds/englishhtml/S5230.htm
) and i'm sure you would be able to taste it in your beer if you have any residuals.
If your chlorine problem is bad use a chlorine filter (http://morebeer.com/view_product/167..._Kit_-_10_inch
) and that should solve your problem.