Add an overflow to any aquarium with Eshopps PF series of hang on back overflows. Adding a sump to a tank will allow you to hide equipment and while adding water volume making your tank more stable. Traditional overflows require you to drill holes in your aquarium where Eshopps PF HOB overflows use a siphon to draw water over the wall of the tank without any modifications to your aquarium. In most cases, we would recommend drilling your aquarium and using an internal overflow like the Eshopps Eclipse, but in some situations, a HOB style overflow may be the best option. Hang on back overflows do require more monitoring and safety precautions to be in place, but can be completely reliable if installed properly and maintained regularly. Installation only takes a couple of minutes, and the PF-300 only requires 3" of clearance outside the tank to drain water down to a sump, refugium, or wet/dry filter. Just lower the overflow box onto your aquarium and then connect your favorite type of plumbing to the included 1" bulkhead. Model Dimensions Bulkheads U-Tubes Recommended Tank Size Max Flow Rate PF-Nano 4" x 2.5" x 8" One 3/4" One 10-20 Gallons 200 GPH PF-300 6" x 3" x 10" One 1" One 35-75 Gallons 300 GPH PF-800 8" x 3" x 10" One 1" One 75-125 Gallons 800 GPH PF-1000 9" x 3" x 10" Two 1" Two 125-150 Gallons 1000 GPH PF-1200 10" x 3" x 10" Two 1" Two 150-200 Gallons 1200 GPH PF-1800 12" x 4" x 10" Two 1.5" One 200-300 Gallons 1600 GPH What's Included? 1x Prefilter Box 1x External Filter Box 1x U-Tube 1x Bulkhead 1x Foam Cylinder Screw(s) and Wind Nut(s) Starting the Siphon: can be done with a 1-foot piece of airline tubing. Start by filling the aquarium until water flows into the intake box, and then using a cup fill the external box with water until the U-tube end is covered. Remove the U-tube and place one end of the airline tubing into the U-tube. Replace the U-tube into the overflow making sure that the airline tubing is at the apex of the bend and using a pump like a Tom's Aqualifter to suck the air out of the tube until it is replaced with water. You may be required to fill either the internal or external box with more water as the siphon is created. Once all the air is removed the airline tubing must be removed or submerged. Once the siphon is created it is important to keep air bubbles from forming in the U-tube. If you find bubbles forming, it could be a variety of things from too little flow to microbubble build up.
