Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Fountec Algicide

Bought the large container of this to use in my outdoor concrete fountain. Directions indicated to use a spoonful or less to keep the water clear. You could put a cup in the fountain and this stuff does not work. A complete failure of a product. I have bleached the fountain, let it dry for several days and then refilled it. Put 4 spoonfuls of this junk in the water of a clean fountain - 4 days later the water was turning green. DO NOT WASTE YOUR MONEY ON THIS PRODUCT. It does not work.