How much water do you normally add to a waxing machine

No need to add water.

A wax therapy machine is a device used to heat and melt wax therapy wax blocks without adding water. Wax therapy wax blocks are made up of specific ingredients that are heated to melt them for use. To use the wax therapy machine, simply place the wax therapy wax block in the machine and follow the machine's operating instructions for setting and heating.