Ah, sorry, i thought it is a GPX cooler so i was confused about "both" pumps. Maybe the problem is the position of the reservoir.
So for my understanding. You put the water into the reservoir and you start the pumps but nothing happens? If yes, the problemis the position of the reservoir. Because the position of the Eisbaer LT is higher than the reservoir and the pump cant suck the water, like all water cooling pumps. So there is only air inside the pump and no water.
Change the tubes.... go first into the Eiswolf cooler, it is deeper than the reservoir. So the water can flow alone to the Eiswolf pump. And go from the radiator in the top down to Eisbaer LT so the water can flow from there alone to the Eisbaer LT pump. That should work.