Algae Problems, Blah.

[Travillion]

Great information. Thank you both.
I figured 20% weekly changes was quite a bit, but I guess not. What is the suggested changes for a 28G?
Also a random question here. When doing water changes, should I leave my skimmer running or turn it off? The water gets so low in the chambers that it almost runs dry. I'm scared that if I turn it off it will restart and take another week or two to get going again.