How to Make an Aquarium Pot Scrubber Air Filter
Using the design of the DIY Sponge Filter, you’re basically switching out the sponge material (or open cell foam) with nylon pot scrubbers. Sponge filters are great for biological and mechanical filtration, but pot scrubbers are proven to have more surface area, which means even more biological filtration. People with a small tank and a large bio load will appreciate this filter, as it takes up no more room than the average sponge filter and triples in efficiency.
Materials for the Scrubber Filter:
Nylon Pot Scrubbers
* And everything else that goes with an air filter: motor, tubing, and air-stone
Aquarium-safe silicone (optional)
1. Take the two scrubbers and cut out a hole in their centers, making them look like donuts. Try to make the holes slightly smaller than the width of the pipe.
2. To secure their donut shape (as the center is what holds the scrubber together), use fishing line to tie and bind the interior walls. I used four pieces.
3. Using the pipe cutter, cut the PVC to whatever length you want, but I typically make it 2 inches taller than the height of the stacked scrubbers.
4. Cut the PVC cap in half using a dremel tool and bench vice, so one half serves as a shortened cap and the other looks like a ring.
5. Once you put the remaining cap on the pipe, line up the stacked scrubbers and mark where the holes need to be (lining right up against the center edge of each scrubber).
6. Drill the holes using the power drill and vice. Make the holes smaller than the size of an eraser head. I drill 4 holes per scrubber
7. Take the pantyhose (I usually use two) and shorten the length using scissors. At the end of the foot, make a small cut for the PVC (with cap's end) to get through.
8. Encase the stacked scrubbers in the altered pantyhose
9. Push the pipe through the stacked, encased scrubbers.
10. Stuff the remaining top pantyhose slack down between the pipe and top scrubber.
11. Secure the encased scrubbers with the other half of the cap (ring) on top, to not only keep the scrubbers from floating, but to ensure they are aligned with the holes.
12. Place the air-stone down the pipe so it's sitting at the bottom of the filter. The further down the air-stone, the more suction the filter will create.
When putting the pantyhose on the scrubbers, do this underwater to avoid trapping large air bubbles; it’s practically unavoidable to do it any other way.
If the nylon pot scrubbers cause the entire filter to float, it’s best to glue something to the bottom of it, such as a smooth river rock or décor. Use aquarium-safe silicone and let it dry for at least 48 hours before putting it in your aquarium.
There is definitely more steps to this filter than a DIY sponge filter, because foam usually doesn’t float, can be cut in any way without falling apart, and it’s just one block of material, so no specific alignment is required.
Still, I recommend this filter. Since putting it in one of my tanks 8 months ago, I have yet to perform any maintenance on it aside from knocking debris off once in a while when siphoning, but the snails seem to do the real maintenance. Snails will eat all the caught debris in the pantyhose liner. Shrimp and other invertebrates may keep it clean as well.
While this certainly isn’t the simpliest filter to make, it’s very cheap, small, and has a lot of surface area.