The tank can be replaced by fabricating a new tank with proper flushing mechanism. The automatic dielectric flow in EDM can be stopped manually in the settings. We had successfully used deionized water as dielectric by installing a separate tank with flushing mechanism. I have attached a photo for your reference.
It is better to use two separate tanks that also have separate outlets. If it is for university experiments (n for industrial work), two separate tanks can be moved and the experiments performed.