Thank you! How much chlorine do I use for a 10,000 gal. pool and how often? I have another question. I just accidentally had to refill about 1/3 of my pools water. The color is still green after adding floculant and vacuuming to waste. What do I need to do now? When the water was low, I noticed that the walls were brown stained. Could this be causing the green color, since we've shocked it 3 times since opening it? Also, do pool stores always manually test water with tablets? I thought they used a machine, but was surprised to see them doing a lot of manual testing.