Fresh water tank and RV antifreeze should never be used in the same sentence. Certainly not in the camper!
Multiple dilutions and rinsing are really the only cure. Pink taste seems directly related to the time the pink stuff remains in contact with the tank -- or the water lines. No reason to leave it in the water lines over the winter either. Once all the water is gone neither the antifreeze nor air (in the empty water lines) will freeze. Use your compressor to blow it out.
The only real purpose of pumping the system full of antifreeze after the water is blown out is to be sure the water pump has no water in it. I doubt that takes a cup.