I'll just mention that many, many people don't bother with the Pink Stuff except to pour it down the drains to fill the traps and put a little in the bottoms of the grey and black tanks.
The reason is that it takes so much water to get the pink taste and color out of the fresh water in the spring. And with most of the US in drought conditions, it's just prudent to use the 'Air' method for your fresh water lines.
Air method uses an inexpensive tire pump to blow water out of the fresh water lines starting at the inside shower head. I just open the lowest faucet and blow it out there. Also remove the pump and drain it.
