Self made overflow?

[Natureboy71]

I never found quite what I was looing for in search.

A long time ago I remember a guy talking about how he took a regular tank (like 300+ gallons) and created and outside overflow that went down below to basically a 50 gallon tank underneight the large one filled with filtration media and then somehow pumped back up into the tank.

Has anyone done something like this? Or seen how it could be done?

Thanks.

 

[greatfulxdead]

There are many threads on this if you search in the DIY section. You could either buy an HOB overflow, build one, or just drill your tank. then all you need is a sump tank and a pump.