AG vinyl liners & calcium hardness

[CarlD]

The use of calcium to reduce foaming makes sense in spas (waterbear has recommended 120-150 ppm and that seems to work well in spas) where foaming can be more common due to the low water volumes so high bather load, but in a pool it's not normally a problem as Ben noted.

I'm guessing that this is actually creating what is called in household water, hard water, which is why water softeners are popular (we have one). Hard water is notorious for being difficult to form suds in, for breaking it down quickly, and, of course, for leaving scale on everything. So it makes sense that if you make the water harder, foaming/sudsing will be more difficult. I realize this is different in that hard water is usually other metals, particularly iron and copper, but calcium is, of course, a highly reactive metal, but a metal nonetheless.

[chem geek]

I'm guessing that this is actually creating what is called in household water, hard water, which is why water softeners are popular (we have one). Hard water is notorious for being difficult to form suds in, for breaking it down quickly, and, of course, for leaving scale on everything. So it makes sense that if you make the water harder, foaming/sudsing will be more difficult. I realize this is different in that hard water is usually other metals, particularly iron and copper, but calcium is, of course, a highly reactive metal, but a metal nonetheless.

Hard water is usually from magnesium and calcium, not from iron or other metals that aren't very high in concentration. Magnesium and calcium form a precipitate with soap such as magnesium or calcium stearate. This is why soap doesn't suds well in hard water and how soap scum forms. To reduce foaming in spas, one could use magnesium instead of calcium if one wanted to.

[CarlD]

Hard water is usually from magnesium and calcium, not from iron or other metals that aren't very high in concentration. Magnesium and calcium form a precipitate with soap such as magnesium or calcium stearate. This is why soap doesn't suds well in hard water and how soap scum forms. To reduce foaming in spas, one could use magnesium instead of calcium if one wanted to.

OK....so I was right for the wrong reasons! It IS creating hard water in spas just to reduce foaming.