I did a water change and was dosing my liquid fertilizers and carbon supplement when my plants started pearling. That’s nothing out of the ordinary, but there was one stem plant that had its top cropped of during one of my trimmings. It had bubbles pouring out of it at an incredible rate. I have a picture and a very short clip of this.

My guess is that the hole in the top of the stem is just the fastest way for oxygen to escape the plant, so that’s where most of the bubbles exit.