[Ranchugirl]

Actually, I use it with my ponds outside, but I guess you can make it work in a tank as well. The whole idea is to provide the fry with proper filtration after the sponge filters aren't enough anymore. I have a tiny little drill bit that can't be much wider than a hair, and it works great.

Ingredients:
- one narrow, higher plastic container
- drill with very small bit, and a bigger one
- one 3 gl bucket
- plastic hair rollers and sponges for media
- small fountain pump from Lowes/Homedepot
- small tubing to go with the pump
- some river rocks to secure narrow container

Except for the drill, the pump and tubing, I got everything else from the dollar store.

I drilled many holes into the narrow, high plastic container with the smaller bit - small enough so the smallest fry can't swim through the holes. Then I put the river rocks into the container, a layer of about an inch. Next comes the tubing to the pump, and the pump itself goes into the narrow container. If the rim of the container is below the water level of the tank/pond, put something underneath, so its about an inch or two above the water level. Reason being - you don't want any fry ending up in the container from above. Its a small pump, but it can kill a fry.
The bucket you'll be using as a filter, so fill it up with the hair rollers and/or sponges (whatever filter media you want to use). I put my cycled sponge filter in there as well, just to get the bacteria multiplication started. Stick the other end of the tubing into the bucket, and fasten it with the handle of the bucket. At least that worked in my case, but you might find another way to prevent the tubing from accidentally slipping out of the bucket. I then turned the pump on and let the bucket fill up about 3/4 up. I started drilling one hole with the bigger bit, about 3 inches below the bucket rim, and watched if the bucket fills up more, which would have led to overflowing. I kept drilling holes at the same height until the water level in the bucket was just about 3/4 of an inch above the holes, and it stopped there. You might need more or less holes to keep the water level constant in the bucket.
Voila, that's it. If you have the drill already (which I did), then your costs for this filter are very minimal. The most expensive item was the $17 pump.

I'll attach pictures tomorrow - I took some, but it was already too dark, and you can't make out much on them.

[koko]

Good tip and DIY. Ranchu I think im going to make this a Research page. :D

[The Fish Whisperer]

ranchugirl did you ever get pictures of your contraption??