Good start. Pics are a bit noisy and could be clearer and sharper. I see your using the 7D and 100mm lens. Sweet combo.
Some tips:
- the streaks of debris suggest to me that you didn't turn your pumps off first. Always a good idea, as is cleaning up the streaks during post processing.
- set that camera on a tripod and use a remote shutter release or self timer to avoid jiggle while pressing the shutter release. Using the tripod will allow much longer exposures than you could ever get hand holding.
- to reduce noise, set your ISO as low as you can. I shoot my tanks at ISO 100 always. When should you turn it up? When you can't get the right combo of aperature and shutterspeed without doing so.
- shoot straight through the glass, completely perpendicular to the front of the tank. Shooting at an angle through glass introduces distortion.
- shoot in RAW mode and set the white balance during post processing. You'll have much more accurate colors without the "too blue" look that most reef pics show when relying on the camera's auto white balance.
- have fun. Experiment. Play with settings. If the resulting image isn't good, delete it and try again.
- post your pics, especially the one's you're having trouble with. The people here are generally good photographers, and very kind with their suggestions.
HTH.