Factorio Forums

https://imgur.com/a/1Q2h1wf
I was trying to make it so that if I have more light oil then petrol it would crack the oil into petrol (pretty new to circuit network)

You have not defined an output signal.
Beyond that, you are overcomplicating your setup, you neither need any decider nor different circuit networks or colors, just connect one tank of each liquid and your pumps and set the conditions in the pumps.

oh great thanks!