The yellow drainage fluid is serum and has just a little blood, while the other dark fluid is mostly onld blood and a little serum.,
Color is OK
The darker drain fluid is from more blood and less serum or fluid. Over time the color changes to a clearer color.
It is not unusual to have different colored drainage into each drain after surgery, especially in the beginning. The darker drain is draining an area where you probably bled a little bit more. It is generally nothing to worry about. It is not necessarily a predictor on how long the drain will have to be in place. Your surgeon will follow you and make those decisions. Sometimes one drain is pulled out before the other one. Best wishes to you!
most important point is that your drain color must progress towards straw colour is 3-5 days and also the quantity of drain must reduce,if it persists for more than 7 days and remains red then you must contact your doctor.normally the drains stop in 3-5 days