The ReefDoser Quadro comes with 4 dosing pumps and can independently control up to 4 dosing pumps. The interval controller allows for adjustment of the duration of the on/off cycle for each pump over a broad time span--from seconds to days. The ReefDoser can automate many tasks in an aquarium:regular dispensing of trace elements and fertilizers in salt and fresh water aquariumscontrolled addition of Calcium and bicarbonate into coral reef tanksaccurate dosing of Kalkwasser into coral reef tanksautomatic feeding with live phyto and zoo plankton