The broken bladder can block the flow out the drain valve. If you are sure the tank is bad, drill a hole in it just above the weld that goes all around it and then another one on top or remove the air valve stem. You get water out the lower one and air in the top one. The water can be very rusty and stain whatever it gets on. I used to take the tank out, drag it to a floor drain and lay it on its side or its top, and drill 3/8" or 1/2" holes letting it drain into a sump pump hole or floor drain.