Powering LED strips with two power banks and they randomly change different colors when i use the second power bank
These are USB power-banks? You need a way to tie the grounds together somehow. Try tying all the ground lines from your LED strips together and also connecting a wire from one of the LED strips to a ground line on your Arduino. 

The USB connections should connect ground between the power bank and the device it's connected to, so by tying the grounds on the LED strips together, that should connect the grounds on the power banks as well.