Metal Control


LifeTime Supporter
May 24, 2007
Staten Island NY
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?



TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
If you have metals in the water they can deposit on the walls/floor of the pool causing unsightly stains. This process happens most easily in fiberglass pools, then in plaster pools, and least easily in vinyl pools. Basically, there needs to be far more metals in the water in a vinyl pool to cause stains than it would take in the other two. Metal Control is one of a great many products that bind to the metal in the water in a way that prevents it from depositing on the walls/floor of the pool.

If you don't already know you have a problem with metals then I would not use Metal Control. Everything that you add to your pool has both positive and negative effects. If you don't need the positive effect there is no point in risking the negative effect.

Algecide is typically added right before closing to precent algae from growing in the pool while it is closed. This is worth doing. However, there are good algicides and not so good algicides. The not so good ones are cheaper, and thus likely what you have. A not so good algecide can cause the water to foam and attracts insects to the water where they die and make a mess. Neither of these are too serious at closing time, so it is probably worth using the algecide.


LifeTime Supporter
Apr 24, 2007
Ashland PA
I would not put in the metal control before closing even if you have metals - it will eat the chlorine, and it will also bring the ph down - and you don't want to do either of them when closing.