This filter is for my 5.5 gallon cherry shrimp tank
that I recently set up. Cost wasn't so much an issue, and I like to keep myself busy, so this project was great.
I used 4" PVC fittings for the main canister body:
1 threaded clean-up cap, which I drilled two holes into: one for the filter output, and one for the power-head electrical cord:
Next I glued in a 1/2" threaded to 3/8" elbow barb for the output:
then i spliced the powerhead cord and ran it through the second hole:
then, clamped the powerhead output to the threaded end of the hose barb with some 1/2" vinyl and some worm clamps:
The powerhead is a henri studios ps2 that my girlfriend had laying around from an old project. it's supposed to pump about 80 gph, but with 8" of head and the frictional resistance of the tubing length, coupled with the flow restriction from the bio media and intake sponge, i estimate the true flow to be only half of this. Once the powerhead, cord and barb were all positioned nicely I put a generous layer of epoxy over both sides of the holes i drilled. Then I taped the electrical cord back together and let it set.
Next I had to figure out what to do with the rest of the canister body. In the original design I had an endcap drilled and tapped by my girlfriend's dad so i could screw in a 3/8" inch barb:
Then I tried to drill a hole for the heater, but not taking into consideration the shortness of the canister body, I cracked the heater tube when screwing the whole assembly together. The powerhead rotated with the thread direction, and crushed the heater as I assembled it. Thus I had a nice, tapped end cap, with a gaping 1/2" hole, and no heater. I then realized that I should probably make the intake diameter larger than the output, and scrapped the whole endcap idea.