Welcome to TFP.
If you're constantly getting air in the filter you have a suction side air leak somewhere. The fact that the bleeder valve never sees water and that there's air coming out the return jets confirms that.
Start by looking at all the common places.
Remove, clean and lube the pump basket lid o-ring.
Remove and reseal the drain plugs. There should be at least 2.
Check the skimmer weir to make sure it's operating freely
Check the water level to make sure the skimmer isn't creating a vortex.
If it's none of those, run water over the fittings while the pump is running and see if the air stops.
Also, tell us what equipment you have. makes, models, etc. and a pic of the pad would be nice.