My friend gave me an HTH pool winterizing kit that included a Quart of Metal Control and a Quart of Algaecide. The metal control claims to prevent staining and the Algaecide (as you probably guessed) prevents algae. My questions are:
What stains can you get from Metal?
Can these stains affect a vinyl liner or just plaster?
Does anyone have positive or negative experiences with these products?
As they were free, are they worth using?