[ccp4bb] zinc with HEPES

[Rajesh Kumar]

Dear All,
This question sounds simple but I dont know the answer.I was preparing a 24 
well crystal screen. When I try to use 10 mM  ZnSO4 with HEPES (pH 7.6) buffer 
it precipitates. I tried both ZnCl2 and Zn acetate the effect is same.  I dont 
know why this Zn in not compatible with HEPES.Could you please tell me why is 
this?I appreciate your help.
ThanksRajesh