If that hose is coming from the tank to the pump, then it is a suction hose and needs replacing. If you starve the pump long enough, some damage can occur. A new suction hose should not cost that much. A wire insert might help. If that hose is a new hose, was it designed for suction, or just plain hose?
If that is a new stiff hose, then you have a blockage somewhere, filter, inside tank obstruction, etc.
You can try blowing air back through the suction tube, but might get messy.
You could do a test of the pump by removing the suction hose, and block off the tank opening, and using a new hose, suck fluid from the container, and dump the pump output flow back into the container.