A couple of thoughts,
a) Are you holding the dropper bottles perfectly upright
b) Are you forcing the drop count or letting it fall by themselves
c) How fresh are the reagents
All the above are factors and you'd benefit from the Magnetic stirr
a) Are you holding the dropper bottles perfectly upright
b) Are you forcing the drop count or letting it fall by themselves
c) How fresh are the reagents
All the above are factors and you'd benefit from the Magnetic stirr