eagle9252;778660 wrote: most have a piece of acrylic turned at an angle and it fills up with water behind it.
eagle9252;778696 wrote: OIC.
some have spray painted or you can overlay it with some lexan and drill and tap some rock shelf's on it, some of the new tanks have lined corner over flows. with holes about midway. so when the water goes over the top it is to create a suction and pull some water from the middle of the tank as well.