Things You'll Need
- Rectangular acrylic box
- Small saw
- Aquarium-safe silicone
- Vinyl tubing
- Filtration media
Instructions
Cut out a small rectangular piece on one side of an acrylic box; 1/2 inch tall and 1 inch wide will often work.
Secure the cut-out piece of acrylic to the box beneath the cut-out section. You are making a place for the water to exit the box before it overflows. The lip created by the cut-out piece of acrylic will guide the water back into the aquarium. Use aquarium-safe silicone to secure the piece.
Adhere the hooks to the box with aquarium-safe silicone so the box will hang on the back of the aquarium. The hooks should be on the same side that you attached the lip in the previous step.
After the silicone cures, hang the box on the back of the aquarium.
Attach the vinyl tubing to the powerhead and place the other end in the rectangular box. This is where the water will enter the filter and should be on the opposite side of the overflow.
Fill the box with filtration media. What you use depends on what you are trying to remove and whether you have a saltwater or freshwater tank. Some choices are live rock (for saltwater tanks), granular activated carbon, mesh filtration media and phosphate sponges.
Plug in the powerhead and check for leaks. Watch the filter carefully and make sure it doesn't overflow or leak water onto the floor.