How to Update user balance Automatically?

hello i want to run an investment website where member will invest and i will give them profit. i am using e-wallet script for payment gateways .. http://ift.tt/2vaFYGs

i want to know how i will update my member balance automatically for example i will give him 10% profit of amount he has deposited what i can do so that after 24 hrs user current update by 10% automatically? please i need a comprehensive answer.