Low-tech, broke ecologist's filter.

[Gill Blue]

to convert nitrates you need an area with very low oxygen levers for anaerobic bacteria to develop. some people do this with slow moving water areas in sumps or seperate filters. pond matrix and poret are also supposed to generate those oxygen deprived areas deep inside the materials.

I hear you on the snails. all my tanks have MTS, common pond, and bladder snails. at least the ones they don't get eaten in.

I don't understand your purpose with the charcoal... are you using it as a biological filtration media? just someplace for the bacteria to live on? I'm not aware of any practical filtration performed by un-activated charcoal.

 

[Andyroo]

Charcoal will be alternative to very coarse foam but also bioball or ceramic media: a) cheap, b) clean, c) porous/odd-shapes, d) light. An "activated charcoal" aspect would be nice, but I'm not expecting or planning for it.
Small fragments (thumb-size) should trap course particles (leaves, roots) while still allowing small biota to enter & consume.
Lightweight, so can rinse/backwash with the hose, or by lifting/shifting & shaking the canister.
Fragments (bamboo) will be somewhat flat-ish, so likely to interlock, stack and/or imbricate maybe with channelling. This will allow such low-flow & anaerobic areas. However, it may also not lock, stack or settle well or at all, which would give a rolling, activated-bed effect that would be cool, but would also degrade (grind up) the charcoal itself and make a quick mess of the sponge. Will see...
Finally & moreover, nitrogenous wastes are to be primarily removed by plants in/around/hanging from tank (outdoors). I just want this system to keep the bits removed and/or digested and/or shredded down with good flow in the tank, min maintenance and min electricity bill.
A

 

[Andyroo]

Shows the current coming out of the 1.5" inlet pipe.


This is one of the black mullet playing in the filter outlet. Upline from pump/filter & outlet is 1.5" as that's what i had on-hand.


one of the mistakes, even though he's less than half as psychotic as either of his brothers. He's been relocated.

The system as it was maybe a year ago: 20Gal chemical drum hanging suspended with pump external, mounted on the post . It's since been adapted with the pump is now internal to the filter with the wire-inlet sealed with putty epoxy, and inlet & outlets are reversed with a 1.5" pumped pressure outlet coming from the bottom. Often leaks from the primary seal, but just drips. Not leaking currently.

 

[Andyroo]

ah- can't figure out how to keep repeat pics from happening, apologies.
This last one is the tank itself, though an older photo. The idea of hanging the filter (although risky, certainly) is to have the tank as part of the view and an otherwise largely unobstructed view. Maybe too much art...