Hello. My pool auto-fill is a Korky 528 "anti siphon". It is fed from the hose bib going through an additional anti siphon valve. Is this second anti-siphon valve redundant? It is currently leaking and I would rather plumb it direct if I can. Thanks!

You can remove but you will need to fill the pool manually. That is an anti siphon FILL valve used to keep the pool filled. <$10 at HD, Lowe's, ACE etc.