Been using SAWYERS for years and it works, but it can be expensive......So I was told to try this, as it's the same chemical as SAWYERS....This will last a few years, I was told mix 2oz. to a gallon of water, and use it as you would SAWYERS. I purchased from Tractor Supply, but I had to order online and shipped FREE to my local store, cause they claim it's not sold in stores....It was under $11.00....