I just use dry chlorine for degassing my ally melts. About a teaspoon for 6-800 ml of liquid. On my last melt I had a much larger volume of liquid ally, about double, so I roughly doubled the dry chlorine too. But the resulting casting was much better in terms of porosity. So if I double the volume of metal and double the volume of CL why is the net result different? Have I not been using enough CL to start with? Is there a minimum amount of CL required to get the chemical reaction needed? If i went 4X with the ally could I stay with 2X the CL and still get a good product?