How to make 317 pink?

I bought 317 sassy sister from uncle Fat 2 weeks ago.  The flowers are now opening but they are so pale that they look almost like Irish flirt.  How can I make them pink?

sassy sister 同 irish flirt 本身係姊妹，花樣似就唔出奇。
只要初開嘅時候有些少帶紅，將來會慢慢變深~

又或者加光，葉柄及葉面會呈紅色，花色亦會隨之變深...
個人比較愛淡色一d

Thanks very much Noel.
Yes, there is a tiny bit of pink in the centre of the flowers, so hopefully they will grow more pink gradually.  As I already have Irish Flirt, I hope the sister will look a bit different.