Backyard Aquaponics
A place to discuss aquaponics

hi guys. Yesterday I drove about 3 hours each way to meet & chat with Dr. Mike Mcgee (caribefish.com). The man has a real cool setup! The thing got me wondering, I'm sure I need a clarifier or filter of some sort for an NFT system, but would I really need one for a growbed system? If not, what do you do with all the gunk that builds up?

Thanks!

Put composting worms in the growbeds. They can eat the gunk. Yummy!

Is it any particular worm? I got plenty of worms in my backyard!

Red Wigglers or Tiger worms. Probably not what you dig out of the dirt. Or maybe you would get the right kind (if they are indigenous) if you pulled them out of your compost heap. Unsure about that.

Well I googled red wiggler & it looks pretty much like what we have!

Toss a few in and let em go to work. I suspect a few worms will end up in your grow bed reguard less if you assist them or not. Strange that, I found a few and do not remember adding any. ...shrug...

i have a makeshift clarifier on my nft, the best reason i can say to use one is fertilizer for the dirt garden.

MW.... this is the classic difference between an aquaculture operation and an aquaponic operation....

The gravel growbeds have been found to act and replace the separate clarifyers, skimmers, bio-filters etc that are utilised in aquaculture operations.

Not only do the growbeds and plants convert and utilise the nutrient rich water, effectively cleaning and filtering it.... they also trap the solid particles from within the nutrient stream and over time break them down providing much needed trace elements and minerals.....

Where you wish to employ NFT techniques it's usually suggested that you utilise nft channels AFTER a growbed or in this case utilise a gravel (or other media)) bio-filter before the nft to remove most of the solids which might otherwise cling to the root balls and/or clog the dispersal grid lines.

Sounds good guys! Thanks!

I saw VB's GB (6' by 3'), he added about 6 compost worms to his bed and 6-8 months later they were thriving, worm capsules were in abundance as well.

He told me how many he added after I had purchased ~800 and spread them in 3 GBs

NFT requires supplemental solids removal. NFT should have a biomechanical wheel or some sort of fluidized bed filter to settle the solids before channeling them to the NFT troughs. The major difference between flood n drain and NFT as I am sure you are aware is the distribution of solid waste. Aquaculturists tend to rely on bio mechanical removal of solids and uv sterilization to achieve the same results and also tend to not understand aquaponics too well as they are trained to rely on proven methods such as biomechanical filtration. This is why I have forgone NFT becuase it requires supplemental methods of solids removal. DWC is somewhat of a compromise in this department and I am experimenting with that right now successfully. I think a good compromise if you are running NFT is to add a gravel grow bed between the disharge from your rearing tank and the NFT channels. This will clarify your water and retain the solid waste and allow you to grow/harvest that fertilizer without removing it from the system and disposing of it. This is of course assuming you are running a self cleaning tank.