Before I do anything, I’m stripping the Cinch system off my Halcyon BP. I won the whole thing 2 years ago, but it was causing major problems in the pool yesterday. Kept getting loose, causing my tank to sit very low on my back.
Tighten your waist belt more? The only way for the shoulder straps to loosen is if you have slack in the waist. I dive doubles with a cinch and it’s never “gotten loose” on me.