FED...Iam cool, only mixed 3 vials at once...its definitly good!!! no problems, didnt go bad...I had put 2cc of water in each...so I was pulling out 20u on the pin, which =2ius.....all is good...thanks for the info, now I know how much to mix, and I'll do 1 at a time from now on....Iam fairly knowlegable with this except for the math part, sometimes I get confused , especially when people are telling you something that does not make sense....THX