DIY Large canister filters

Chris asked about the large canister filters that I talked
of earlier this week and wanted to know a bit more. He
uses the 200 litre sized ones, filled with spun plastic 
mat type material that is about 4 inches thick that is 
commonly used for trickle filters. It is rolled up and slid
into the barrel. The unit sits below the tank, fed from an 
overflow with a prefilter. The PVC inlet pipe is connected 
to the lid of the barrel, with the outlet on the side of the base.
The outlet feeds a small Onga pool pump that pumps back
to the tank. 

His pond uses a similar system, but uses three barrels 
connected one after another, the final one being filled with
sand, having a network of PVC pipes inside like a 
conventional pool sand filter. 

He primarily grows plants, but has Aussie and Papua-New Guinea
rainbows in them aswell. He did use metal halide, but has just
switched to 6700K flouros. BTW- his plants are just wonderful.

On another tack, Sydney Aquarium use PVC sewer pipe and 
step down fittings for their canister filters, each one costs about
AU$5 in all, and they use them in great quantities. They have
screw on fittings and can be removed, cleaned out and replaced
in about five minutes. Much cheaper than the commercial