Alright, since you have a light that doesn't have to sit on the glass, I highly recommend that you completely remove the glass tops. Then, take on of your powerheads and let it blow water across the surface of the water. This will greatly increase aeration. Instead of having the powerhead blowing up at the water.
Also, if your skimmer isn't pulling out any gunk over the course of a few days, the skimmer is doing nothing for your tank. I highly recommend that you upgrade your skimmer and add a canopy.
Nothing wrong with working for money. An allowance goes a long way if you can do chores around the house. Cutting grass in the Summer also helps add a little cash in your pocket. I wouldn't completely count on your parents for everything - so if you can, try putting yourself to good use.