The 75g that I recently purchased came with an overflow already setup. However, it used a 1" flex hose, and I want to just use pvc instead. The flex hose connected to a threaded "pipe" below the aquarium, so I purchased a 1" joint - one side threaded on the inside and the other smooth. However, the threaded side is barely too small, and the smooth side is too big. Any ideas as to what piece to use?