>>The concentration of the syrup seems to be more important than that 
of the acid.
 
The sugar syrup recommendation is 1:1 (sugar to water) by weight or 
volume.  (They found using just water did not work - either it was 
not taken up by bees or did not stick to mites.)  The concentration 
of the OA crystals (you don't use a liquid OA) should be accurate. 

I suppose one could eyeball the amount of OA crystal amount but that 
will leave you guessing as to what happened should things go wrong. 
In the studies where they looked at lower and higher concentrations, 
they either had insufficient mite kills or harm to the bees.

Waldemar

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