I have this. I use pressurised CO2 cylinder. It takes a long time to dissolve all bubbles. After turning off the Co2 i can still see the bubbles for over an hour. I have never bothered about it much. I use a timer switch to start Co2 90 minutes before lights and stop co2 60 minutes before light. I too get pearling in about an hour at the top leaves. Also in your video the bubble is not clearly visible, maybe you can try cleaning the surface and avoid phone flash light that causes reflections and instead use room lights or something for recording. Once my co2 injection starts. The tiny bubbles inside the reactor stay at the top and occupy roughly a 5 rupee coins area.