[Pavel Chaloupka]

you definitely do not need any p.a. or pharmaceutical quality, you should be able to buy it in normal shop, it will be much cheaper even though it probably does not matter much as you need like 1/3 of flat teaspoon once a week using 5 liter buckets like I do. Of course best is to take that amount and shape it like line and devide this in to 7 equal parts and add this on daily basis. This way it is safer as adding to much of glucose may lead to fast developement of bacteria in the culture and the culture solution could become stinky. As I repeat with all the cultures, less and more often is better untill you get a feel for it.