Whats the deal with winter "Stain-Away"?

[el_steak]

I was planning on simply balancing my water, shocking it and maybe adding a bit of Poly 60 for the winter.

Now I saw that the winterizing kit sold at the pool stores also include a "stain preventer" (stain away?) to protect the liner during the winter.

Is that anything necessary or is it just homeopathy for pools?

 

[JasonLion]

If your pool has metals in the water you often need to add something to help hold the metals in solution over the winter. If you don't already have a known metals problem then I wouldn't worry about it.