I need to replace a worn out yellow ring on a Kohler toilet, but shut-off valve in back won't turn. Will have to turn off water to whole house. For some reason, my sister, a retired real estate agent, thinks doing so could cause a major plumbing problem. No, she did not specify. Thus, can I simply take the water hose out of the flush valve thing, fit it in a long vinyl tube that ends in the bathtub, and redirect the water for the few minutes I need to put a new ring on the flush valve? Seriously.