View Full Version : DIY biofilter

Evil Slimy
06-01-2008, 06:24 AM
I wanted a biofilter for the 55g. I thought about sumps, overflows, etc... This was what turned out to be the simplest, and most failsafe solution. Ugly, but plants/driftwood will cover it up completely and some day I will move it to a sump.

The blue cap on the bottle is a water-tight threaded cap so it will be very easy to rinse/clean media. [I know it's water tight because we use them around the house and despite our being as clumsy as hippos on skates, they never spilled a drop.]

I took a 3 inch section of 1/2 inch vinyl tubing, ran it under hot water to soften it and pushed one end over the output of a powerhead.
I cut the other end of the tubing at 45 degrees and pushed it through the bottle opening (where you'd drink from). It fit snugly so I pulled it through with pliers. I did not have to use any sealant (no sealant in the whole project actually...).

To create an outlet, I melted several small holes at the bottom of the bottle, on the outer edge so it would spray outwards. I choose to make the holes small so that some water pressure and turbulence would build inside the bottle and increase exposure to the biomedia.

Filled it with seachem matrix, which as far as I know has one of the highest surface areas. According to their rating, the amount I used should provide enough biofiltration for 75g. The filter pad is from another tank. It was in there just to jump start the system. I removed it and added more seachem matrix.

Since the pictures were taken I replaced the powerhead with a maxijet 600 and I added a sponge on the intake (over the long plastic strainer for the maxijet powerhead). So far it sustained 12 tetras and a severum with a pig-sized stomach without any issues.

06-01-2008, 08:06 AM
Interesting, but wouldn't an aquaclear powerhead with a quickfilter housing attached work better?

Evil Slimy
06-01-2008, 09:33 AM
I believe the quickfilter is mostly a polishing mechanical filter. The purpose of the filter above is to create increase biological filtration. I wasn't able to find an internal filter that provided room for that much bio-media.

06-01-2008, 11:00 AM
Interesting idea. There might be ways to improve on the design.

06-01-2008, 04:30 PM
The quickfilter is intended as a mechanical filter but the housing can be filled with other media instead, with or without the plastic "core". I use a sponge block in one, and blue/white bulk filter material wrapped around the plastic cores in two others. They are used as prefilters on powerheads, but I don't see why seachem matrix contained in the housings would be significantly different.

06-01-2008, 09:27 PM
What an excellent idea, especially when the money you save can go toward a really cool fish or something.

06-02-2008, 06:07 AM
Seems to me it would work better with the tube running to the bottom of the bottle and the holes toward the top. Upward flow would agitate the media more than downward flow. You could even ad an airline to your powerhead if it can utilize one and use the filter as kind of a wet dry. Still I respect your resourcefulness and ingenuity