There is a product called Stocktrine. It is a liquid chelated copper algaecide formula in a concentration suitable for dosing stock water tanks, troughs, and small ponds. Treated water can be used immediately for stock watering. Two oz treats 500 gallons. If you are treating a pond I wouldn't let them drink right after you treat but should be fine if you make em wait a few hours. There are no restrictions regarding water treated with Copper Sulfate for irrigation, livestock or other domestic purposes just as long as you treat in accordance with the label. Use only 2.6 pounds of copper sulfate per acre foot.