As I run pink through each of the taps and toilet...the water is forced out and pink finally flows. This means that the p-trap should be pretty much full of pink when I'm done at each tap. All the water and diluted pink solution ends up in the black/grey tanks which I then dump and I haven't experienced any valve issues after this process. For reference we see down to about -37C in Jan/Feb so its a pretty solid freeze here. For sure getting pink to outside shower, black tank backflush, washer hose, ice maker and fresh water intake one way valve are more of my concern as water can get trapped in those lines and burst.
Daryll
