If you have cleaning fluid the first thing I would do is flush the drain lines to make sure they are clear.
You should be able to remove the white tube line that runs to the captop from the pump. If you have a syringe you can even just force air (from the end of the line that connected to the captop) through the line. You would feel a bit of pressure in the syringe if the line is blocked. If it is blocked then use some solution to force into the line and be careful for the pressure and back spray when removing the syringe.
If you know the lines were already clear than are you seeing ink going into the drain bottle from each line. May take a couple cleanings to get ink through the drain lines again.
If you do a cleaning and watch the captops when the heads move away from them, is there ink pooling in the captops? If so does the pooling go away shortly after the heads move. If this is so there may be a blockage that is not drawing and clearing the ink propper.
Now for adding cleaning fluid to the captop, you should be able to put in (using a syringe) just enough to fill to the top of the rubber on the captop. Parking the heads over them will wick into the heads and hopefully flush or soften debre.
I tend not to like doing a soak as the clear lines under the head (on my CJ printer) get ink in the lines and then they block and plug. Not sure if your printer has those lines but if there is another set of clear lines, they should be free from blockage.
Instead of a head soak I take a clean swab and put cleaning fluid on it and gently push up under the head (DO NOT RUB JUST PUSH UP) rubbing can damage the head. By pushing up you force some fluid into the head and this has unblocked nosles when I have had problem, and if regular cleanings have not helped.
After either the head soak or the swab push, do a couple cleaning cycles and another test print.