Backyard Aquaponics
A place to discuss aquaponics

Hi! texas ken here: I am just starting to put in a system, I know not one thing about aquaponics except what I have read here in the last bunch of hours. My fish will be channel cat in a 300 to 400 gal hot tub ( the only piece of equip. I have so far) #1 question. what is better the raft or the gravel system and why is it better? I will try to keep my questions simple but please expect a bunch of them. Oh I will be using a wood grow tank lined with a 10 mil vinyl. I don't know where to find the pertty plastic ones I see in most of your pictures. thanks Texas ken

And you call that a simple question Ken....

Welcome Ken....

It's not really so much a question of what method is better or best... but more a question of what point of view of aqauponics you coming from... or heading towards...

The UVI, floating raft model is a proven "commercial" system... and is intended and designed from that perspective... with associated requirements for land area, infrastructure, filtration and set up costs...

Flood & drain media beds are more applicable to home production... require less space, setup cost... and include the filtration/infrastructure components within the initial design... and within the growbeds themselves...

It is possible to setup a floating raft system in your backyard/farm etc... if you have the space, filtration equipment and knowledge and understanding of how DWC (deep water culture) works...

DWC is a continuous flow recirculating system that relies on pre-filtration/solids removal... and oxygen/aeration injection within the channels upon which the rafts sit...

Flood & drain on the other hand... utilises the media filled growbeds as the filtration method and entraps the solids to provide mineralisation...


They can be continuously pumped and drained by autosiphons... or intermittently pumped (by timer)... and drained by standpipes...

The repetitive flood & drain not only removes solids from the water, provides mineralisation for the plants... but oxygenates the water for both the plants and fishes benefit...

Ask away... I'm sure you have even more questions now

Thanks fresh by nature I believe you just made up my mind. the system I am going to build will be 75 to 100 sq ft of growing beds in my back yard for my family. the gravel makes more since now. thanks Texas Ken.

+1

Yes flood and drain media (grave) filled grow beds make much sense as they package all the filtration (bio-filter and solids filter) and plant growing space into one neat package. (FYI, gravel filled grow beds are also a great place to grow some composting worms and they help take care of some of the extra solids and turn them into plant usable things.)

I'm all for lumber and liner grow beds, that is what I did for the most part on my system.
Uniseals can plumb though liner, I've not had any leaks yet in mine, you just need a backing of appropriate thickness behind the liner for support. I'm kinda partial to the EPDM liner but it is costly. The 5.5 foot wide role of it is perfect for just under 3' wide by 1' deep beds of whatever length you choose. I have 5 beds that are 8' long and one bed that is closer to 30' long.

Before you get too far along in your design, look up CHIFT PIST as it is a major design element that can have a huge impact on system maintenance.

Good Luck and welcome aboard!