My process of taking found parts and creating a bog filter (aka veggie filter) for my turtle tank. Bog filters are used primarily for ponds, but is working quite well for this indoor tank.
My…eh hem…highly technical drawing of the filter…I modeled this with anoxic filtration in mind. Here’s a good overview of the anoxic process if you’re interested:
The turtle tank. Since the canister filter I had broke, I’ve been doing 100% water changes every week. That’s 40 gallons of water every single week.
My haphazard gathering of materials. I don’t really have a workroom, so I worked in my living room. That’s a 3 gallon beverage dispenser, a small submersible pump (90 gph, I believe), a pipe extender, a slotted plastic basket, screen door replacement screening, waterproof tape, aquarium sponges, 2 sizes of biological filter medium (really just different shapes of baked clay) and gravel used for planted aquariums.
Action shot! Kidding. Just a bad photo. Here’s the beverage dispenser. I figured since the process would be to push water from the tank up through the filter, the dispenser was perfect. It already had a preformed hole in the bottom and was water tight.
The top, however, had no such hole, so it was drilling time! I planned to use a hole saw to cut the 1 1/2″ hole I’d need to feed the pipe extender kit through, so I needed to drill a 3/4″ hole for the center of the hole saw to sit in. If you’ve ever drilled a hole in acrylic, you know that it takes a low, slow drill to keep from cracking.
First hole, 1/4″ bit.
Second hole, 1/2″ bit.
I’m not entirely sure how exactly the pipe extender is supposed to work for plumbing, but after combing the plumbing sections of three hardware stores, I thought it would work well for this. It had both a female and male adapter side, and best of all, the pipe itself accordioned (that may not be an actual word, but you get the point…) into the shape I needed. Since this outflow needed to make a 90 degree angle into my tank, the flexibility was key. A little RTV silicone and a 24 hour curing period make the whole shebang water-tight.
I’m both cheap and opportunistic, so when I saw this plastic spout that came with the dispenser, I felt I needed to at least try to reuse it…
Fortunately, the interior diameter of the remaining spout was a clean 1/2″, and I knew I could make that work with the tubing I’d need for the pump.
Here’s the slotted basket I used to house most of the media and the plants. I cut out a slot in the top to accommodate the outflow pipe, and lined it with left over window screening I had from a time when I *may* have put a 2×4 through a screen door in my last apartment..
The outflow pipe in place!
Here’s a photo from the side that shows the pump (bottom right corner in the tank) that I covered with a filter sponge to act as mechanical filtration and keep large solids out of the main filter, and how it attaches with tubing to the spout I cut apart.
Close up of the joint. Totally water-tight!
As a plant hoarder, I had no need to buy any plants for this project. I used cuttings of several plants I know don’t mind having wet feet and are good ol’ heavy feeders. Their job, after all, is pulling nitrites and ammonia out of the water before it goes back into the tank. Let’s see….I have a few pothos cuttings, three kinds of ivy, and a sprig of schefflera.
All done! It’s been running for a week now with no problems at all. As you can see, the water pours into the tank, which made a very, very loud splashing sound. So I built a filter baffle to quiet the sucker down.
Two weeks on and the filter is a complete success! There has been no leakage of any kind, the tank water is clear, and the water quality is high with no ammonia or nitrites to be seen. And, my favorite part, the plant cuttings I put in the top of the filter are growing like crazy! Check out the new little sprout off the schlefflera. Grow little friend, grow!