Nicolaas The Heuy Hung range has now become unobtainable, because of the chemicals used in them. all the powder chemicals used to compose this excellent product may not be imported into SA. New government regulations. What i would suggest with reference to your discus, firstly how big are they? The reason why i ask, because if they are bred at a too young age there growth stops and the amount of fertile eggs will be very few. Are your discus eating and are you giving them a varied diet. Prof. D . Bellstedt will assist you in this matter .