Hey makmak you could probably find this info via the net. There are a couple of formulas that you could conjure up with. One of the very first and earliest known solutions is called Knudson C.
FYI Also my breeder-friend has been successful in his experiment using a commercial orchid fertilizer as a substitute formula in his culture media solution in order to be able to cut down on the costs. I just do not know as to what the exact percentage/proportions are that he has used.