I have recently bought an old brother edm wirecut, i am using ion resin crystals to make the water the correct ion level for cutting,to get the level down is easy, i just enter the value i want and it does its thing. the levels range between 1 and 6, when i am at 1 how do i get the level back to 5,do i have to add more water to the system or with the ionisation unit do it for me?