My 3 yr old female albino cat keeps pooping in my tub, how can I stop this? She has never done this! I am appalled by her behavior and I cannot figure out how to stop her, she only does it at night when we are asleep, during the day or if we are awake she will use the litter box with like the other cats we have. Does anyone have any advice on why she is doing this or how I can stop her? please! I'm sick of cleaning my tub every morning!