Flowering Nutrients

Hey People: I have one plant in DWC as a test run. Going very well so far. I have just flipped to 12/12 and the nutrients that are currently in the res are for veg. How do I introduce my flowering nutrients. Do I add gradually over the next few weeks until it's time to do a total res change, or do I change the solution and put flowering nutrients at the outset.
Here are some photos....

I'd switch right away!

the first two weeks of 12/12 is still veg..
everyone does it different, usually what ever is the easiest and most convenient for you will work great

Thank you for your support and advice~!