The multicontroller allows sequential mode- basically, pump 1, 2, 3, 4 and then 1, 2, 3, 4- you need 4-8 pumps to use this. Tide mode, one pump on, one pump off. 2-8 pumps can run this program. Pulse mode, 1-7 seconds switching between two settings. Their are two seperate settings for two channels, with branch adapters, up to 4 pumps per channel. The single controller only runse with pulse mode and the photo cell is an accessory.