K2639 Liquid Controller

I am looking to use the K2639 liquid controller kit to “top-off” my aquarium when the level drops below a certain point. Looking at the instructions, the relay is activated when both S1 and S2 are “wet”, and it is deactivated when both are “dry”. I would need it to do the opposite of this; to activate when the water level falls below the low sensor (dry), and then deactivate once the water level reached the high sensor (wet). Can this be done with this kit?? And if so, what do I need to do to make it work??

Thanks,

Jonathan

Kit allows use as level controller, to keep the level between ‘low’ and ‘high’ sensor, without modifications.