DIY: Baffle Filter

Baffles are dividers in an aquarium's filtration system that force the water under or over them. They help control the flow of the water and divide a filter container into different sections that can then be used for different purposes. Usually, baffles are added to an external filtration system called a sump. You can use any food-safe material to create the baffles, but acrylic or plexiglass sheets are easy to cut, bend and attach to the sump.

Things You'll Need

  • 15 gallon glass aquarium (or larger)
  • Acrylic sheets
  • Saw
  • Aquarium-safe silicone
  • Filter media
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Instructions

    • 1

      Measure the width and height of the inside of the empty aquarium. This will determine what size you should cut your baffles. This is also a good time to consider what you want to add to the chambers you will create in the sump.

    • 2

      Cut the acrylic into sheets the same width as the aquarium and an inch and a half shorter. You want water to flow over or under the baffle without overflowing the aquarium; thus, the baffle needs to be a bit shorter than the height of the aquarium. Cut four baffles from the acrylic.

    • 3

      Insert one baffle into the aquarium at a third the length of the aquarium. This baffle divides the incoming water on the left, from the filtration section on the right. Push this baffle to the bottom of the aquarium so that the water will flow over it.

    • 4

      Adhere the baffle with the aquarium-safe silicone. This will act as glue to hold the baffle in place and prevent water from leaking under or around it.

    • 5

      Insert the next three baffles to form a bubble trap on right third of the aquarium. A bubble trap helps remove small bubbles created when the water splashes in the sump. The first baffle should be against the bottom of the aquarium so the water flows over it. The second baffle should be lifted to the top of the aquarium so the water flows under it. Finally, the third baffle should also be on the bottom of the aquarium so the water flows over it. This forms a U-shaped chamber that will allow the bubbles to float to the top of the water. Leave about an inch between the baffles.

    • 6

      Fill the middle chamber with your desired filter material. Some good choices are filter floss and activated carbon. For saltwater aquariums, consider adding a deep sand bed and a protein skimmer.

    • 7

      Let the silicone completely cure before adding water to the sump. Once fully cured, the silicone will be safe for fish.

    • 8

      Add your plumbing from the display aquarium so that water flows into the left side of the sump, over and under the baffles, and then flows out of the sump on the right side.