well i use 1.1 firbe wraped tank and i can though a hopper and 4 140 pots b4 it starts to die,just a standed A5 with e-grip and flatline,so i reckon theres a leak or something wrong inside.As for balls the best i,ve ever used is spec ops but its discontinued now,but most paints are ok apart from tournie paint as its quite brittle and more designed for supair markers(ego,s and the likes)