It shows the 2 hang on overflows. The UV Sterilizer on the left. The 3/4" PVC Spraybar. The 1/2" CPVC line is for the UV Sterilizer.There is a powerhead in the "cage" (see cages in the DIY section of the site) on the left which pumps the water into the Sterilizer. From there it goes the length of the tank via the 1/2" CPVC and comes out under my Xenia that lives on the right side of the tank.