I wore my Spry Cool Racerback the other day and got yellow green armpit circles (mildly mortifying) and thought I had the dreaded pH problem. However, it turns out it's not me, it's my deodorant causing issues. The same thing happened to me today when I first put the tank on and I hadn't even started sweating. I did a quick test by dabbing some of my deodorant (Mitchum Power Gel) on the hem, shown in the above photo, and you can see how the fabric changed color. It washes right out, thankfully. I remember a similar problem happening with the Snorkel Ambition Pullovers a few years ago. Before I put the tank in the wash I tried a putting a different deodorant (Secret solid) on the fabric and it didn't cause any change. Anyway, just wanted you to be aware of this issue.