After a successful hydroponic growing season last year I thought it would be fun to build a NFT system and hopefully remove some of the issues I had with my old recirculating bubbler build.
The main issue was the roots managed to get down into the 19mm pipe and restrict the water flow too much meaning that when the pump came on the first few buckets filled really quickly and then overflowed, even when I reduced the pump run time to just 15 minutes every hour. The taps also got blocked up but roots and dirt. Cleaning out the 19mm pipe was next to impossible.
I bought a couple of 6m by 100mm drainage pipe off trademe along with 4 end caps delivered for $118 so it was quite good value. My deck is only 4m long so I had to chop them to size. I bout 6 100mm pipe saddles from bunnings for about $7.50 each to hold the pipe in place and also up off the deck to make it easier to clean.
For spacing between the two pipes I only used 100mm as the front row I am planning on growing herbs, lettuce and other various stuff which should be interesting as they will get the same nutrient feed as my chillis. Once I had the saddles attached to small bits of wood and the pipe mounted I then used masking tape down the top center to mark out the locations of the holes. I went for 350mm spacing between each so should end up in a huge jungle.
For the wick pots I used standard 86mm pots from Switched On Gardner which were $0.80c each, the hole saw I used was 82mm which gave me a tight fit (I tested it on the 2m pipe off cut first).
This time round I decided it was important to include filters at the start of each 19mm pipe so any loose material that makes it into the system gets caught and does not mess up the system or pump. The holes in the end caps were 22mm and I used T-Hat grommets to join the filter onto it. The height I used was just above halfway which I hope keeps a nice water level yet allows the water to drain before it gets up to the holes for the wick pots.
The reservoir I bought off trademe also and it was cheap at $15. I cut a square access door and attached it on with small hinges and a lockable latch. The holes I drilled were 22mm which fit the outside circumference of the 19mm pipe perfectly.
Time to get some plants in and do some testing!!!
[19.10.2013] I was having issues with the flow through the 4mm pipe I had used to the water feeds into the larger NFT pipes and they were also leaking a little. not much but just enough to be annoying. I tried adding some sealant to them which worked for a few days then they started to drip again. I thought it was best to go to a slightly larger pipe to increase the feed lines so they are not restricted and instead of using 4mm joiners I could then use 13mm to 6mm tee adapters and change the main 19mm tube down to 13mm to match which was a biggie as the outlet on the water pump was 13mm anyway. This is now working much better with an unrestricted flow and no leaks. I now have some plants added too.