No, you cannot mix pumps with the Advanced Controller. If you have the 250, you can only use another 250 or a 150. If you want to use the 280, you will need to purchase a 280 Advanced Controller.
Here is a compatibility tabled that will help you see what is compatible with what. Click on the link below and then go to the "More Details" tab...
http://www.coralvue.com/maxspect-advanced-gyre-controller