I think the effect of k3 is just too small when k3 itself is that small. If you increas the maximum of k3's range, you can start to see some effect. For example replace 0.0000250 with 0.0250 and re-evaluate the Manipulate. Now you can start to see effects when you use k3's slider.

Okay, thanks for formatting that bit of the code. I went ahead and added a toy body:

Manipulate[
 k3,
 {{k3, 0.0000119, Style["k3", Blue, Bold, Medium]}, 0.00000010, 
  0.0000250, 0.0000000050 , ControlType -> Slider}]

This is working fine. So, unless there is some sublety that I'm missing because of the size of these numbers, then problem is in your actual code for the graph.