Orchid is turning yellow?

so I have 3 moth orchids and one of them it%26#039;s leave is turning yellow. I water them once a week and I have them by the window... so as soon as I noticed that one of them was turning yellow I took it away from the window... the leaves was a little red with yellow now is like all yellow... the other 2 leaves my plant has are pretty and bright green





what%26#039;s wrong with my orchid?|||If the whole plant is turning yellow its dying.Most cause of death in orchids is over watering. But I don%26#039;t know what median you are growing them in.Cold draft. Also they don%26#039;t require much lite.I just hope the yellow one produces pups. Also I don%26#039;t know what zone you are in, so it%26#039;s hard to guess whats wrong. I have a few hundred orchids and occasionally one will die.But they always leave me 2 or 3 new plants.|||liver problem hurt and see a Doctor could be deadly can you contact me smoothfriend4u