When I added the nano powerhead, I was also using a air bubble wall. I tried to remove it and after a few days my Discus became listless. I could see a smokey haze on the waters surface. I put the bubble wall back in and even the kuhli came out to play in it. He also plays when I do a wc. When the water fills back in there are bubbles on everything. The Discus tonight were nudging them off the leaves. Since I don't use CO2, I have been told that agitation of the surface is ok. Is there a way to get more O2 in with out listening to the hiss of the bubble wall? It is the only sound in the room.