Larry Lunsford

Here are plans and instructions for a simple filter. The filter is simply a stand and 5 gal. bucket with some media. This filter can be used for a small pond, hospital tank, or quarantine tank.

To build this filter, you'll need the following: 5 gallon bucket, ¾" PVC crosses (3), ¾" PVC Tees (12), ¾" PVC elbow - slip x female pipe thread (1), ¾" PVC cap (1), ¾" barb to ¾" male pipe thread adapter, ¾" PVC pipe (about 20'), pea gravel or lava rock (about 3 gal.), 1" filter padding (about 1' x 6').

Start construction by drilling holes in the bottom of the bucket. I put about 8 holes (¾") in mine. The size or number isn't critical (nothing about this filter is critical).

Next, cut a piece of filter pad to fit in the bottom of the bucket. The pad should fit snugly to hold in the gravel. If your padding is thin or weak, you may want to put two pieces on the bottom. I also cut a piece of padding to form a cylinder about 8" tall that fits on top of the bottom pad. I did this to make it more difficult for the gravel to work around the padding. I also put padding on the top. The top pad will collect most of the debris and can be simply removed and rinsed for routine cleaning.

Construct a stand. I made mine out of PVC pipe and fittings. My stand has three levels of horizontal X's - one that supports the bottom of the bucket, one just above the bucket (to keep everything secure), and one at the bottom (to keep it from wobbling). At the end of each piece of the X's are Tees. The X's are connected by vertical pieces that fit in the Tees. I assembled my stand by simply pressing the pieces of pipe into the fittings. I didn't use glue since it was quite sturdy with just a press fit and I'm always changing things anyway. You could eliminate the stand and just set the bucket on bricks or concrete blocks.

Make a spray bar. I used ¾" pipe with a cap on one end, and an elbow and barb adapter on the other end. Drill a bunch of holes in the spray bar. You may need to experiment a bit with the size and number of holes. You want the water coming out of the spray bar with enough pressure to get water well aerated and well distributed over the top of the bucket, but you don't want to overly restrict the water flow. Cement the parts on the spray bar since it'll be under pressure.

Connect your pump to the spray bar using vinyl tubing and you're done. I sized the legs on my stand so that the bucket would be mostly out of the water. This lets the media operate in wet/dry mode which is most efficient for biological activity. For routine cleaning, just rinse the top pad. Periodically, you'll need to remove all the gravel and rinse it out well.

There is nothing critical about any of the details on this filter. You can use bigger or smaller containers for the 5 gal. bucket to suit your needs. You can use any of many media choices in the bucket. Whatever you do, just keep it clean.

Click on pictures below for larger image.

  Assembled stand.

  Spray Bar.

  Filter operating in stock tank.

Koi