Swimming Pool Acid

[waterbear]

It has about the same side effects as using dry acid (sodium bisulfate) without the convienence factor. With a SWG, hydrochloric acid (muriatic acid) is my first choice.
Edit: Muriatic acid adds chloride ions to the water so the salt (sodium chloride) that the SWG uses is 'reformed' after generating chlorine. Sufuric acid and dry acid do not do this. (Richard, I know this is very oversimplifed and not totally accurate but it is close enough to the correct annswer without getting too technical). As Carl said, it's ok to use but when it's gone you would be better off with muriatic acid in my opinion.