This week, I had an epiphany with my suction-side auto-vac. (Sta-rite Pool Shark (discontinued))
I was about ready to give up on it....it never patterned well and had a habit of tangling (looping around) on itself....ending up cleaning only a small circle of my pool.
For reasons I can't remember, I added another six feet of hose I had laying around....more hose than the man. recommended but put it on there nevertheless. Voila! Ole' "Sharkie" now covers the entire pool and entangles himself probably 80% less than before. He's still slow, but seems to have gained his brain back and actually now cleans my pool pretty well.....well enough so I can get a few more years out of him or until Ed McMahon brings me that check.
Hope this info is useful to someone else.