L,
Looking at your first pics with the red valves.. And.. assuming it is plumbed like the diagram...
The upper 3 valves going into your pump are....
The red valve on the left is controlling water coming from your two skimmers.
The red valve in the middle is controlling water coming from what I 'assume' is your pool cleaner..

The red valve on the right is controlling water coming from your bottom drain (sump)..
The lower red valve, that is next to the surge protector, is for controlling the water going back into the pool.. This valve should always be fully open in normally operation.
Right now your skimmer valve is set to shut off about 50% of the water coming from the skimmers.. We normally run with this valve fully open.
Do you have some kind of cleaner connected to the diagram #12??
Having the bottom drain shut off is not a big deal...
Please tell me what problem you are trying to solve by adjusting the valves..
Thanks,
Jim R.