fuel pump loosing prime

[groggy1]

last year I installed seperate fule system , sump in tank ,filter, fuel pump for nitrious system only. before I use it ( only use it mabey once a month) I have to take fuel line off at selinod and let the fuel punp run or I dont get any flow , It also seems like pressure fluxuates so I have to reset it . is this normal or is there a problem . thanks