How muchy load required for for transfering air for ballon at higher level to lower level of the ballon ?

1 meter height tank having with water. 2 balloon kept inside water it is connected with a hose pipe, in that balloon ,1balloon kept at lower level and another one kept inside water at higher level. higher level balloon filled with air .now i need to transfer air from top level to bottom level so how much load required for compressing(weight) at top balloon? pipe dia is 1 inch,and top level air filled balloon 7kg capacity to lift upword.