Posted: Fri May 18, 2007 1:51 pm
I had an Aquaclear 50 (for up to 50-gallon fish tanks) in a ten-gallon tank. To make it almost noiseless, I siliconed a piece of plexiglass to the lip and had the end of the plexiglass just under the water level. If you don't use plexiglass, raising the water level will make it somewhat less noisy (less distance for the water to fall), but raising it to the lip of the filter is high enough to allow your turtle to escape if there's no barrier from preventing him from doing so...
You have an Aquaclear 20? This is a very small filter (so is the Aquaclear 50, so the model you have must be the mini?). I wouldn't expect it to pick up debris at the bottom of the tank, especially if the intake tube isn't at the very bottom (even then...). Filters are for filtering water, not for vacumming up debris at the bottom of the tank.
"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-