How much Stock Tank Secret do I need? The amount of Stock Tank Secret you need to put into your stock tank depends on two factors. One is the surface area of the tank. An average stock tank has a surface area of about 10 square feet or 2 feet wide by 5 feet long. The depth of the tank is not a factor. For each 10 feet of surface area, use one bag of Stock Tank Secret. If your stock tank is extremely dirty, either dump and scrub the tank clean OR use two bags of Stock Tank Secret. How long does Stock Tank Secret last? A bag of Stock Tank Secret normally lasts two months. In tests, it has lasted even longer. One tip to get the maximum life from a bag of Stock Tank Secret is to top off your tank off frequently. Tanks that are allowed to get to very low levels often, may not get as good results with Stock Tank Secret. How long does it take Stock Tank Secret to work? Stock Tank Secret begins to work immediately when it is placed in the tank. However, you may not notice its effect for a week to ten days. At first, you might observe the sides of the stock tank turning black as the barley straw treatment starts to work. If your tank had a lot of dirt and residue built up along the sides of the tank, the debris may start coming off in sheets and do so for about a week. Take a shovel or manure fork and fish the floating debris out of the tank. The water will become clearer and the tank will remain clean for about two months. How do I know that Stock Tank Secret is safe? Stock Tank Secret is completely organic and very safe. Many academic studies have been done regarding the use of Stock Tank Secret’s key ingredient for treating water with barley straw. All studies have proven it safe for all types of livestock and fish. At Stock Tank Secret, we conducted three years of studies at two horse farms. One is Glenncarry Farm, who has more than 70 horses including many warmbloods who compete internationally. No ill effects ever occurred. Can Stock Tank Secret be used in fish ponds? Stock Tank Secret has been used with great success in ornamental fish ponds. These customers report that they no longer use chemicals and that there has been absolutely no effect on the fish and aquatic plants. Calculate the square surface footage of the pond and use one bag for each ten feet of surface area. If you come up with 25 feet, round up to three bags.