From: "@frank.net   
      
   On 11/11/2018 10:44 AM, Oumati Asami wrote:   
   > On 11/11/18 14:39, Libor Striz wrote:   
   >> Oumati Asami  Wrote in message:   
   >>> If this is not the right place for the question, please excuse me.I   
   >>> use 65% calcium hypochlorite as the source of chlorine for my pool.   
   >>> If I add no more than 4 lbs of the hypochlorite, the water stays   
   >>> clear. If, however, I add more, say, 8 to 10 lb, the water turns   
   >>> milky. The fine powder that makes the water looked milky takes 2 to 3   
   >>> days to settle.What could this white powder be? I think it might be   
   >>> calcium carbonate but where does the carbonate come from and why it   
   >>> only happens when relatively large amount of hypochlorite is added?   
   >>> One theory is when small amount of the hypochlorite is added, no   
   >>> enough carbonate is formed. So, it cannot be seen. I doubt it.   
   >>> Judging from the extent of the milky color, even one tenth of it   
   >>> should be quite visible.Another theory is that large amount of   
   >>> hypochlorite changes the PH of the water. I'm not sure what result   
   >>> that would be.Any thought?   
   >>   
   >> You do not say the basin volume,   
   >> so it is not possibke to say   
   >> 4 or 10 lb is much or  not.   
   >>   
   >> You do not say the pH nor the  hardness of  water ( calcium +   
   >>   magnesium content), that affects  the results.   
   >>   
   >> The question is, how much is the vendor suggested amount to add ?   
   >>   
   >> But few thoughts:   
   >>   
   >> Calcium hypochlorite is reportedly less soluble  in hard water,   
   >>   preferably used in  soft to medium hard one.   
   >>   
   >> It is basic, containing calcium hydroxide, so it shifts pH up,   
   >>   supporting calcium  carbonate precipitation.   
   >> Ca+2 + HCO3-  + OH- --> CaCO3 + H2O.   
   >>   
   >> It adds calcium to water, supporting calcium carbonate precipitation   
   >>   
   >> The precipitation  is not proportional  to added bleacher, but   
   >>   occurs above some threshold.   
   >>   
   > I do not know the volume of the pool, its PH or hardness.   
   >   
   > If the ppt only occurs above a threshold, it explains why more   
   > hypochlorite causes the ppt. I just wonder where the carbonate came   
   > from. Can it come from rain? I thought acid rain usually is caused by   
   > H2SO3, not H2CO3.   
      
   There is 0.04 percent carbon dioxide in the air around us.  Water   
   absorbs it.   
      
   --- SoupGate-Win32 v1.05   
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