Backyard Aquaponics
A place to discuss aquaponics

Fair enough.... but why not just stick in a gravel growbed before the nft... and use the growbed to filter the solids.... and the solids to grow veges?

I agree.

Thanks Rupert!

Depends on the height of the system, by having a clarifier on top it works like a water reserve with only one pump and flow down through the NFT. The clarifier will be less heavy than a growbed full of gravel or hydroton.
But it is sure that it is the best to have plants in the biofilter of the system i spoke before.

I would probably say go for a bed filter since it will do two things at once but space and weight requirements may not allow that.
Amacatfish, your little diagram is nice but do you think that a little strawberry tower biofilter is enough biofiltration for a system that must be stocked heavily enough to support that much NFT?

Depends on the surface area available for bacteria on the media, go for scoria and i suppose it would cope with the porosity. I'll check the numbers for the biofilter volume compared to food input and post them.
And the diagram is an idea not finished, i'll be trying something like that on my deds pond this summer.

Amacatfish

Link might be useful http://leisure.prior-it.co.uk/build-diy ... lter.shtml

CG also had a novel idea of using bottle caps as a bio filter. The interesting thing was that they are bouyant, so you could place them in the vortex filter and they would stay at the top providing extra surface area, and slowing the flow ( bit like a hybrid bead filter).

That is just a brilliant idea Sleepe.
Thanks, such a cheap biofilter, recycled also!!!
Cheers

I was watching dirty jobs the other day & they went to some fish farm in Cali. The bio balls they had looked pretty much like bottle caps to me (although they weren't).

I like the bottle cap idea. Anyone know if there would be any problems/drawbacks to using bottle caps?

You can integrate the media and nft in the same trough/bed if you`re crafty enough

To my mind, having an evenly distributed layer of solids within easy reach of all the roots is more beneficial than having a huge amount of solids upstream in a seperate bed.

Anaerobic pools of water in each cap?

I like bio-bale. Its very expensive, but its just shredded cellophane, aka easter grass or celo shred. It has a surface to volume ratio of 800:1 and it cheap and "food grade"; though that is questionable.