oxygen in water, rollers on filter

[aprilabaxter]

I have just adjusted my powerhead to point toward the surface (I only have one in a 55G) it just ripples the water and there are no bubbles in the water now. I understand that is good from what I have read on this forum. My filter just trickles water, is that the only source of oxygen for my tank? Also, I have taken the cover off my filter because I discovered that the rollers were not turning because the light was pushed up against it. I don't think it stopped for more than a day or two. I checked it when I was testing and my ammonia was up. Will it hurt my biofilter to leave the cover off so I can see them?

 

[cap'n pete]

It won't hurt anything. The cover is there to reduce evaporation, keep dust out, and hide the ugly inside of the filter. As far as oxygen exchange. Even stagnant water surface exchanges oxygen (although not very well). The rippling of the surface and the filter should give you good oxygen exchange.