I'm doing a long needed cleaning on my beer lines (3). I've neglected these pretty badly over the last year while I moved and I was planning to tap three new kegs today. Two of the lines came clean pretty quickly with starsan (clean water flush), BLC for 15 min (clear water flush), starsan (clear water flush).
The third line spit out a bunch of white film and after two cleaning cycles it's still spitting out white film. I'm doing a third BLC soak for 30 min, will follow that with another starsan soak and will wash, rinse, repeat as needed until it's clear. I plan to replace the shanks with stainless shanks soon and will replace all of the lines at that time.
If I were going to guess I'd say this looks like a lactobacillus infection. The last thing run through this line was soda. Thoughts?