DIY Wet-dry dump filter

In a post on the forum a couple of months ago, a member of the Capital Cichlid Association described a filter type that was kind of what you would get if you put a wet-dry sump above the tank, instead of below it. He called it a “dump” filter, and it intrigued me, because it lets you derive all the advantages of a sump without having to drill your tank for overflows, and using a less powerful (and thus, less expensive and more energy efficient) pump.

Around that same time, I bought a 110g tank from another CCA member, and I decided to use one of the double-drilled 20 long tanks I had laying around to build a dump filter for this tank. Below is a picture of that filter during a water change.

The basic principle of the dump filter is that you have a powerhead or pump in the tank that pumps water up into the dump filter, where it passes through your filter media (two pieces of Poret foam in this case), and then drains by gravity back into the tank.  Here’s where the pump (a Mini-Jet 606 in this case) dumped water into the dump filter:

From there, it would pass through the two layers of Poret foam to the overflows, and then back into the tank:

This system worked really well, and the Poret foam provides an enormous surface area for beneficial bacteria to grow on.  But the way I built this concerned me, because I had a 3/4 full 20 gallon tank (probably about 140 pounds or so) sitting on the upper rim of the 110g.  This just felt like an accident waiting to happen.  I needed something lighter weight, and it was not really necessary for the dump filter to be full of water.  In fact, an even better filter could be made as a wet-dry.

So over my Thanksgiving weekend, instead of stuffing myself stupid with Turkey and fixings (we actually got Chinese take out, LOL) and watching football (I found it liberating to get my Sundays back when I stopped caring about football), I built the wet-dry dump filter described below, which cost me a total of about thirty five bucks (since I used some Poret foam I already had lying around).

The new system starts with a Quiet One 1200 pump that does about 296 gallons per hour (this will turn over the tank’s volume about three times an hour, which is pretty good).  I picked this up at That Fish Place, which has one of the best selections around, and I was there anyway to attend the ACLC meeting.  The nice thing about That Fish Place is that they have all kinds of PVC fittings in stock, and I was able to open up the box for the QO-1200 and say “get me a fitting that screws on here and goes to 1/2″ PVC”, and twenty seconds later, the guy comes out of the back with the perfect fitting.  Nice!

From the pump, 1/2″ PVC rises to a T-fitting, and then to two PVC ball valves.  The one off to the left will eventually go into the laundry room, allowing me to do water changes without even dragging out the python.  Yay!

To distribute water over the filter media, I built a loop of PVC that would have holes drilled in it:

Since I was going to drill holes in these pipes, I was careful to mark the orientations of all the pipes *before* I drilled and cemented them together:

Then I made a little jig to make drilling the holes a little easier (I don’t have a drill press, which would have made this a snap):

Once I had all the holes drilled (I used 3/16″ holes, and spaced them far apart early in the loop, and gradually closer together, until they were only about one inch apart near the end), I dry fit everything together and tested it, mainly to see if I needed more holes.  Luckily, it looks like I judged the number, size, and layout of the holes perfectly!

Finally, I used PVC cement to permanently seal all the joints, and then did a final test, which I let run for a good half an hour, so as to rinse out any residual PVC cement odors:

Now, to prepare the media container, I used one of those plastic storage containers you can get quite cheaply at most department or crafts stores.  I used a 62 quart size, since we already had it lying around, and since I had used it before as a temporary fish container while moving fish from one tank to another or doing re-scapes.  I drilled two 1″ holes in the bottom corners and installed bulkheads I picked up at Aquarium Depot:

I wanted to have as little standing water as possible in the filter container (to cut down its weight), so I mounted the bulkhead so that it protruded out of the bottom of the container.  Then I cut several two inch lengths of 1.5″ PVC to use as spacers underneath the sheet of Poret foam, since I wanted this to be a wet-dry filter (I did not want the foam sitting in any water that might accumulate in the bottom):

Finally, I stacked the Poret foam sheets on the PVC spacers, interspersing two new sheets with the two sheets I removed from the 20 long dump filter shown above.  Then I cut a notch in the side of the container for the spray bar loop, and put the container in place over the tank, and did the final assembly.  Then I turned the pump on, and Voila!  It worked.  Yay!

The final touch was to use the clip-on lid that came with the container, which helps cut the sound a little bit, as well as keep dust off the filter foam and decrease the likelihood of splashing:

And here’s a picture of the complete setup, which is not very pretty, but is highly functional, pretty cheap, and quite powerful:

I’ve only had this up and running for a few days, but I’m pretty confident it will work well.  And since it’s using a pump with a much higher output rate, and the foam from the previous filter plus two new sheets of foam, I should be able to get even more filtration capacity.  Now I can probably double the number of peacocks and haps in this tank!  :-)

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