Hey Jester I am having the same problems with running my Tsunami upgrade on one 3/4 intake. If I try to fill more than one bag at a time the first pump just robs most of the water from system. I am planning on drilling three 1" holes for the new Johnson pump redo and just using the 3/4 intake for my center bag which is my smallest. Let me know how it works if you get yours done first.