(ALGAECIDE) is a powerful all-purpose algaecide. The Yellow Stuff quickly eliminates all types of algae breakouts, and is also a highly effective algae preventative. The Yellow Stuff is safe for all pool finishes and works all major pool sanitizing systems. Swimming can resume in a few hours. Please note: This product is not available in AK, AL, AR, CO, DE, HI, ID, IL, IA, ME, MS, MT, NC, ND, OK, OR, SD, UT, WI and WY.