This will be the first time I try blowing out the lines before I put in the antifreeze. In my old motorhome I had to replace two toilets foot valves because of winter freeze. I can't agree that if you see pink you can be 100% sure you got all the water out! Somehow in my particular foot valve some water remained and froze and cracked the valve. I am 110% sure that I got plenty of antifreeze thru the line into the toilet yet I had to replace the valve. New motorhome -two toilets to worry about so I am going to try blowing the lines first, then run antifreeze into the system then re-open the low point drains operate the toilets to let those lines drain and the sinks and shower as well as the clothes washer hook ups.