You can see from the posts on this topic just how confusing the amounts 
can be for a proper OA solution especially when the dihydrate is used. 
The density of OA is about 1.9 gm/ml so add two ml of water  to one OA 
and you get 3.9 gm. Divide that by 3, since there are three molecules 
involved and you get 1.6 gm/ml for the density of the dihydrate. So you 
cannot even rely on densities when talking about OA unless you are very 
specific.

Interesting, that if you take the 35gm specified by Canada and consider 
it pure OA, it would be close to but on the low side by 5 gm of the 
recommended winter dose in Randy's article. But who knows.

There was a study made a while back in Germany on the different 
concentrations of OA and what worked best and the 3-4% solution range 
was most effective. Higher hurt the bees and lower than that was less to 
not effective. The 70gm dihydrate/1ltr H20/1kg sugar gives a solution in 
that range. 35gm of dihydrate would be well out of the range and 
probably not very effective.

I goofed on my computations quite a while back and came up with 
recommended amounts for OA using cups and teaspoons. Interesting that 
what I ended up with is the current suggested amounts for winter (1 2/3 
tsp OA dihydrate per cup of water and cup of sugar give about 13 gm per 
cup which is exactly the same as Randy's winter mix).

Bill Truesdell
Bath, Maine

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