Setting time of alginate is best regulated by the:
Though setting time of alginate can be changed or regulated by any of the above method, but most of them leads to changes or aﬀect the properties of ﬁnal set alginate. Only available best method to regulate it is by a speciﬁc amount of retarder added during the manufacturing process.
Also know

Setting time of Fast-setting alginate = 1.5 to 3 min
Setting time of Normal-setting alginate = 3 to 4.5 min
Amount of retarder added during the manufacturing process
Changing the temperature of mixing water
Modification in the W/P ratio
Speed of mixing or mixing time