Rust streak from auto fill on first year pool

Txjole

Bronze Supporter
Aug 22, 2018
288
Wylie/TX
I have a rust streak running down from my auto fill port. Shop vac’d the auto fill bucket, city water has little to no iron, plumbed in with all pvc, fills off brand new arrowhead 486 frost proof, started after I unhooked the auto fill for the winter. Only unknown is I deleted the vacuum breaker off the frost proof and added a straight throw adapter (lead free brass). Chasing my tail here.