Extruded acrylic is fine for sumps, or wet/drys... as long as the tank heigth is not over 12"... making big tanks with it is a bad idea though... smaller tanks are fine,... extruded acrylic is not strong enough for continuous loads. It is a much softer material than cell cast.
NiceGuyNick, when working with acrylic, the cement you use is to weld the pieces together...so welding and cementing are the same thing when it comes to acrylic..Its referred to as solvent welding.