Is this StarSan in my fermenter?

I've always fermented in a plastic bucket. Recently I purchased a 6 gallon betterbottle to use for a Primary..

So I've never been able to see the primary fermentation action!!

This is the first time I've used it and I noticed after about 3 days when fermentation had settled down, there's a ring of white bubbles around the edge as you can see in the pic below..

So is this starsan that has sucked back into the carboy from my blow off tube?

Or is it something else that I need to be concerned about?

Thanks!

Looks perfectly normal to me.

Yeah. Those are just bubbles accumulating in the liquid at the edge under the krausen.

That's one helluva full bottle. Lookin' good!

After the Krausen starts to settle down it will often look like that for a few days. It isn't because of sanitizer.

It's just CO2, yeast & beer. Normal.