I noticed that usually when I do a PWC the water that comes out of the filter is hitting the top of the tank water and creating bubbles. It looks nice and my bamboo shrimp loves it. But yesterday I added a bit of water and noticed that it was a bit high and my filter water wasn't creating those nice bubbles anymore. I took some water out (about 2 cups) and it made the bubbles again. My question is, do those bubbles matter?