HomeMeet PetePete's StuffGuppysPete's PicksSwordtails
RREASEndlersTruth In SpendingShipping FactsWeatherAquatic Animals
PlantsPlatysKillifishCorydorasBreeding Egg LayersCyprinidae
Spend UR $$$  HereCichlidsrecipesPlecostomusAnabantoidsADULTS ONLY
TetrasLoachesStagnation SucksMang Super CrossWHAT THE F--Bichir
JokesPollution SolutionHot New GuppyFish FoodFurcataPHOTO FAQ
Good CrapAuban Tricks Auban Tricks 2Wildfire Angels

This website is dedicated to Ol'Conrad.  He passed away shortly after Christmas, 2013.  He had made stupendous contributions to our hobby through his dedicated and careful breeding of aquatic animals.  He was a good friend and best buddy of Pete's and will not only be missed greatly by Pete, the hobby will forever have lost a valuable friend and asset. But his progeny will live on forever in his memory.

DIY Low Cost - High Capacity Biofilter brought to you by the fishguy_1955  - give his crap a good look.

Go to  http://www.aquabid.com/cgi-bin/auction/auction.cgi?disp&viewseller&Fishguy_1955 to view my items for sale, including the Aragonite mentioned in this article, on AquaBid.com.
This filter costs about $3.00 to build, depending on what you might have at hand, and as shown is more than capable of filtering a 20 gallon tank with a moderate bioload. I'm using it in a 10 gallon because I tend to filter heavily and carry a higher bioload.
Assemble the following items before you begin:

I'm using a cut off two liter soda bottle here, but you could also use a one liter or any other plastic container you wish. Transparent is a big plus for seeing when the filter needs cleaning.
Because I am going for a high filtration rate here, I went with a 1" PVC lift pipe and fitting. The wider pipe lets me use a standard airstone and gives a higher flow than smaller pipe. The pipe only needs to be pushed into the T. No adhesive is needed.
Cut both the container and the lift pipe/T fitting assembly so that the top of the pipe will be a few inches below the surface of the water in the tank the filter will be used in. The lift pipe must not protrude above the surface of the water.
Tubing and airstone are standard and always present in my pantry, as is the polyfoam.
For this filter, since I'll be housing snails in the tank, the media I'm using is Aragonite crushed coral. More on this below.
Begin by standing the lift tube up in the container and covering the T with a few inches of polyfoam. This is inexpensive and very handy to have around the fishroom. You can get a bag for a few bucks in the fabric department of most retail stores. Here the foam is providing mechanical filtration and keeping the inlets on the T from getting clogged with debris and/or the coral.

Now add the primary filter media, we are using Aragonite, to within a few inches of the top. This media provides a place for the bacteria necessary to convert the toxic ammonia excreted by your fish and inverts into nitrites and finally far less toxic nitrates. The main idea here is the the more surface area for bacteria to colonize, the more waste the filter can process. I am using Aragonite, but you could use gravel or lava rocks here as well. Whatever you use must be heavy enough to keep the filter on the bottom of the tank, so bio-balls are out.
The Aragonite coral has two advantages for me here. First, because it is so craggy it has an unbelievable surface area for bacteria to colonize, making the filter super efficient. Second, it will take the ph of the tank to about 8.0 and it will keep it there! You wouldn't want to use this media in a filter for blackwater fish like tetras or angels, but for snails it is perfect and will ensure strong healthy shells without acidic erosion. To lower ph you could use regular gravel and a bit of peat at the top. Whatever media you use, make sure to rinse it thoroughly until the water runs clear before loading your filter.
Next I put in another couple inches of polyfloss covered with layer of rock to keep it down. This is the part you can change out as required, and it acts to keep the lower, high power part of the filter from clogging.
Now the airstone is connected to the airline
The completed biofilter in the tank, running and prepared to cycle.
The operation of this filter is straightforward. The bubbles rising in the lift tube push and pull a column of water up the tube. As water rises in the lift tube, it is replaced by water from the tank, that flows into the filter and down to the T fitting, passing through the Aragonite media on the way down, allowing the bacteria living on it to process the waste by consuming ammonia and nitrites.
If Aragonite is not available locally and you would like to construct this filter to raise your ph, I offer it for sale on AquaBid.com as Fishguy_1955 and you can click HERE to view my items for sale there, including Aragonite.
How To Fast Cycle Your New Biofilter

Normally it takes a month or more for a new filter to get colonized by the needed bacteria. The bottled fast cycle products out there are in my opinion and experience a waste of money. If you or a friend have another tank up and running with sponge filters, you can cycle this new filter in just a few days. Just get it up and running as shown above, then take a couple nice grungy sponges from a healthy tank and wring them out real well just above the newly running filter.

The resultant cloudy muck is teeming with millions of the beneficial bacteria you need, and your new biofilter will suck them in where they will colonize the media. Instant cycle. You can repeat this over a few days while introducing a few small fish or snails to provide needed ammonia for the new bacteria. Just build the population slowly over the first few weeks and your new filter will be good to go!