I'd say ya got way too many filters on it, bypass them for starters, particularly the one before the pump, but that fine filter as well .... maybe the tank sock alone is too much restriction for the volume the pump moves and is collapsing, then opening again when the suction falls

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics