I do not use hot water. Get a brine shrimp net or very fine mest strainer, put the cube of food in it and run cool
RO/
DI water over it until thawed. Then rinse with more
RO/
DI water just to be sure. The "juice" produced is very high in
PO4 and
NO3. I then put the food in a small dish with some vita-chem, selcon and garlic extreme to let it soak for a few minutes. I add some tank water to the dish and then use a syringe to distribute to various areas of the tank.