Is it possible to use Ammonium Thiosulfate instaed of Sodium Thiosulfate as Hypo in Farmer's reducer?? What about the conversion rate?? At the moment I have Ammonium Thiosulfate 58-60% liquid on the shelf. I do need 120 grams of Sodium Thiosulfate and water to make 500 ml. How much Ammonium Thiosulfate (in ml) do I have to add to make also a stock solution of 500 ml?