I have a problem with my suction line for my pool cleaner. If I open the suction line up enough so that the pool vacuum moves around, their is not enough water coming through the other suctions lines and my pump stops working. If I move the valves so that more water is pulled from the other suctions lines, then the pool vacuum doesn't move.

Any thoughts?

Does the pump lose prime and start pulling air when this happens or does the water in the strainer pot just stand still?

I think the water just stands still.

If it's just standing still in the strainer then the issue is hydraulic (vs. an air leak which could cause the pump to lose prime when the suction head was increased). Any chance you could post a picture of your equipment setup?