Understanding Pool filter, 0 PSI?

the filter should have between 5 and 10 lbs. of pressure in it,anything over that and you need to back wash it,and as far as the suction the best way i know to do it is block off the main drain and all but one skimmer opening,and put the hose in it that should give you plenty of suction to clean the pool,does the pool have a double main drain,if not you need to check into that and see if that's a law where you live,and i have no idea what your talking about the "J" thing,be glad to help you can email me through yahoo and i'll help as much as i can,sounds like your a good kid trying to help your mom,i,m sure she appreciates it .