500mg calcium phosphate Convert to sodium monohydrogen acetate dihydrate to obtain the same amount of phosphate

A patient with insufficient phosphorus should take 500mg of calcium phosphate from the physician. Since calcium phosphate only exists in bulk as a technical raw material, I cannot use this to make a preparation. And Calisvit is currently not available. Is it possible to replace this with sodium monohydrogen phosphate dihydrate and how much does it correspond to obtain the same amount of phosphates?