I was walking in our neighborhood the other day, and my neighbor's babysitter, who happens to be a friend of mine, asked me to test their pool water. It was green. So I tested it with my T-100, and it came up 0 CL, and 0 Stabilizer. I gave him the basic scoop on what to do and told him about troublefreepool.com. When I spoke to him later in the day he said the owner didn't want to put bleach in the pool because of damage to the liner, yada, yada, yada. So I said fine, just keep doing what you are doing and get the same results. Yesterday I was driving by and saw him pouring some bottles of something in the pool, and I noticed a few empty Walmart bleach bottles nearby. I had to chuckle to myself.