An example laundry treating appliance includes a tub, a rotatable drum disposed in the tub and defining a treating chamber in which laundry is received for treatment according to a cycle of operation, a treating chemistry dispenser having an outlet and a cup having a siphon, configured to dispense a treating chemistry into at least one of the tub or the drum, a sensor, and a controller configured to at least: introduce a predetermined amount of liquid into the cup sufficient to activate the siphon if a predetermined amount of the treating chemistry is present in the cup; detect whether the siphon activates in response to the predetermined amount of liquid based on an output of the sensor; and modify cycle of operation based on whether the siphon activates in response to the predetermined amount of liquid.