If you start seeing them turning pale, you'll want to add more light, put them in proper soil and start feeding them lightly. I start my clones on a foliar feed, usually at the 3rd week after they have been removed from the mother, when they are starting to lose lower leaves.
Doing this, you will actually be getting close to what a lot of experienced growers like- running a 2-room system (24/0 clone/mother and 12/12 flower), which draws constant electricity from month to month and give you greater efficiency using your space and available lights.