PlanetCatfish.com

I have recently increased the filtration and volume of my tank by adding a 20 litre external filter made from a cold water storage tank rated for potable water.
The filter sits with its top level with the top of the tank, a tube passes from the tank into the bottom of the filter. At the top of the filter there sits a small pond pump which currently tuned down gives a flow rate of about 250 litres an hour.
The first stage of filtration is a layer of lava rock 4 inches deep. Then there are 3 layers of sponge proggressively finer toward the top.
The challenge was setting up the siphon tube from tank to filter, then tuning pump to the right flow rate so as not to overtake the siphon.
This system cannot overflow as the siphon stops the moment water levels equalise.
This is a trial, I dont have any pics (no cam) so i cant show you. I hope to increase the flow rate but for that I must add another siphon tube! Maximum flow on this pump would be 450 litres an hour.
If anyone has any ideas or experiences relating to this I would love to hear about it, Incidentally the total cost was about 30 GBP which is about half what you would pay for the smallest eheim canister filter here.

Thanks
jason

Jason, I am interested in home made filtration and sumps as well. I have done and have been doing a couple of my own. I am trying to grasp the image you've been trying to create but can't make heads or tails of it. If you can't take a picture, how about a drawing?

Hope everything works out.

Mike D.