After talking with the provider, my product resulted to be CaCl2.4H2O and not CaCl2 anhydrous, so I guess that was one of my problems, beeing the other the concentration.
I'm doing a new test with a mixture of 250 Gr. of CaCl2.4H2O + 87 Grm H2O that uppon my calculations should be a relation of 1:1 in mass. Thanks a lot for all the info.
I have another question, this is more dificult, I have read that for the solution of CaCl2.4H2O +2H2O converts to CaCl2.6H2O I have to put some Sr(OH)2 acting as "seeding crystal" I don't undestand the reaction and I don't know how much Sr(OH) I need for a 1KG of CaCl2.4H2O.
Besides that, there is last question about if can replace the SR(OH)2 with Strontium Chloride + Sodium Hydroxide because I can't get Sr(OH)2 but I can get Strontium Chloride or Strontium nitrate.
Thanks a lot guys
Olgierd