Backyard Aquaponics
A place to discuss aquaponics

i want to know the positive aspect in raft method that can make it successful..(e.g. aeration,growbed,water flow, etc)

Hehehe you need to do some reading
The backyard aquaponics shop has a system of rafts
C1

Raft style aquaponics involves a different set of design parameters than the usually flood & drain media growbeds...

And you'd have to start from scratch with the specific parameters in mind...

Generally more suited to a larger "commercial" style of operation.... small scale raft systems IMO don't stack up against flood & drain... or even NFT... in terms of production per footprint...

There is a point of scale though where raft systems are potentially more productive than growbeds.... whether they're better than NFT in the same large footprint... I'm not totally convinced.

Floating raft (or what Hydroponics calls DWC Deep Water Culture)
Basically, a container that has water and a foam raft with holes for the plant pots.
Usually requires lots of aeration for good plant growth.

To apply this to Aquaponics, you will need separate filtration for the water. Yes bio-filtration can take place on all surfaces in a system but solids will need to be removed as they tend to cause too much oxygen demand as they rot or you need some sort of bio-filter that can handle solids without depriving other parts of the system of dissolved oxygen.

Many big commercial systems are floating raft systems. Look in the commercial systems area for earthbound's BYAP commercial system.

Raft systems tend to be big Omek... unless you're going "commercial"... just build a flood & drain system... and learn the basics...

Then... for system #2....

Omek, here's the link to Joel's new raft system... viewtopic.php?f=13&t=5209&start=0&st=0&sk=t&sd=a

Similar in design to that pioneered at UVI....

Google UVI or "Friendly Aquaponics"... for more photos etc..

Here is a thread in commercial systems about a raft system
http://backyardaquaponics.com/forum/viewtopic.php?f=13&t=5209

thanks for the link...

actually im having a thought that this method can be applied for a small system...

and if anybody willing to give me any diagrams... well, just to understand better...

Sure a raft could be applied to a small system but you will need to have some sort of bio-filter. A fish tank and a raft bed alone won't cut it. Between the fish tank and the raft you will need to filter solids and have some method to provide some extra bio-filter. Lost of additional air will probably be needed but it could be made to work if you do some research about fish keeping and filtering water.

Unfortunately, most of us here use flood and drain gravel beds so that is what we know best and have the most diagrams, instructions, and numbers for.

Ok so perhaps you might lay out a raft system this way.
Please don't ask me for diagrams to build the filters, you will have to search for those, I know people have posted some on the forum lately. I've never built an external bio-filter or solids filter that worked well so I don't know how to do it well or size them properly.

it is clearer for me now... thanks TC...

actually my earlier thought on raft method is........

That might work but only if you add filters before the water goes into the raft bed.