getting rid of Cladophora prolifera

I had purchased Toadstool algae (Cladophora prolifera) and dint know that it can become a pest if left open in a tank. i have a 15gal nano soon to be converted to 30gal with sump. i have to huge ball of Cladophora prolifera in my current tank that i will be shifting to my sump but the rest of it i i wana get rid off as it looks ugly. what should i do? will 3days of darkness do the job? or removing it manually or increasing mag levels? i only have softies in my tank. will they get effected if the the tank has no light for 3 days?

 

anyone?