Converting the Hydroponics System to an Aquaponics System (Part 3) -NFT System

NFT System added to Aquaponic grow beds.

 We've been continuing our conversion from a hydroponic ebb and flow table to a closed, aquaponics system. We've discovered some great resources along the way, and encountered a few challenges.

The pond has about a 1000 gallon capacity and after using a media bed sizing tool, discovered we'd be able to increase our media-bed space. We wanted to be sure that any addition we made would increase the aeration of the system, help heat the water, and fit into the available space in the greenhouse. The solution was to add an NFT (Nutrient Film Technique) system would be perfect. NFT systems require a shallow stream of water (and in our case continuous drip), runs through the media to provide essential nutrients to the roots.

The PVC tubes fit with emitters and drains.

I was lucky enough to find four, ten ft., capped-pvc tubes. I drilled for 1/2 inch irrigation hose and added 18 drip emitters on two inch X 1/4 inch tubing. The 1/2 inch lines would be fed off a 3/4 inch feeder hose, run through a manifold, that feeds directly from our pond (soon to be stocked with tilapia). I was looking for a source for a clip to hold the 1/4 inch tubing in place for the individual emitters. I bought the post style version , cut off the post and drilled and glued the clips in the holes (perfect).

Emitters are working and basil growing.

We'd be building the system vertically (space issue) for the individual tubes to drip into each other, before ultimately dripping into the grow beds. Fabricating the rack was as simple as building a four shelved unit and attaching it to the grow bed and the wall. I temporarily mounted the manifold, as I wanted to see if height adjustments needed to be made. Each tube was filled with hydroton and basil and lettuce start (in rockwool) were inserted, one per emitter. I slid the tubes into place and adjusted the drains, so that each drained into the one below it. I fired up the pump and adjusted the valves on the manifold to get flow correct. I needed to make slight adjustments to the sprinkler heads to ensure each are pointed in the right direction.




I had enough starts to fill three of the racks. We'll wait 10 days or so and start the next tube, with additional lettuces.

System seems to work great. The flow is perfect. It fills the lower grow bed at a slow rate, and the bell siphon drains it quickly. Perfect.

Sediment tank will help grow duckweed

I made a few cosmetic and a few practical adjustment to the sediment tank. We'll eventually grow duckweed in this tub and we'll have a couple of filters to help keep any solids from flowing back to the pond. I started the pump and we are now cycling 24 hours a day, for the first time.

We'll start tracking Ph, Nitrates, Nitrites and Ammonia, soon. Hopefully we'll start seeing signs of nitrites and nitrates that will show us the system is working.


To do list...
1. Get duckweed started
2. Start managing the science of the water (checking regularly)
3. Get the second growbed on-line and tee the 3/4 inch feed from the pond.
4. Build a third rack to support adjusting the tubes to drip only to the corner of the bed.
5. Add additional aeration (hopefully only temporary, but I want the water ready for fish.
6. Get fish
7. Start more lettuce for NFT
8. Transplant peppers and cucumbers into growbeds