According to Greg you mix 1 tbsp in 500ml of water. http://www.gregwatson.com/PMDDStoreInfo.htm
I've always used 2tbsp in 500ml since Greg states CSM+B is not as concentrated.
To add more confusion, this time I mixed up 1tbsp to 500ml but I'm dosing twice as much. However, I have the CSM+B with extra iron and it doesn't mix as well as the regular CSM+B. I hope that made things clear as mud