suction problem!

[Watermom]

Have you backwashed your filter lately? If not, try that and see if it helps.

[Poconos]

Welcome to the forum.
Do you have a main bottom drain and if so do you have the valving set to suck only from the skimmer? If you don't have a main drain then when you connect the vacuum hose what happens to the force at a return jet? If you're getting absolutely zero suction when you connect the vacuum hose and still have flow out the returns then water is being sucked from somewhere else. Watermom may be on to something with a plugged filter where you feel suction with your hand but the least bit of resistance on the suction side, like connecting a long hose, cuts what little flow you may have to zip. What kind of gauge pressure are you running normally and when you connect the hose?
Al