Backyard Aquaponics
A place to discuss aquaponics

I've been reading awhile and I've got a couple of questions that I haven't found clear answers for regarding NFT setups, so I was hoping to clear them up and make the info easier to find in the future.
For reference my system will be using 8" (200mm) PVC

1.) Is there an best size net pot to use? Or is bigger better? or does it just depend on the plants? Whats a good compromise?

2.) How much water exactly should be in the bottom of the pipe? (1/8", 1/4", 1/2"?) (3mm,6mm,12mm)?

3.) Is it better to be cycled, or continuous flow? (I know this is open to debate..)

4.) What the best way to drain the pipes? (This depends on 2 and 3)

Links to relevant threads I may have missed / should be included are welcome!

Thanks everybody!
Chance

I don't if anything I'm doing qualifies for "best practices", but my first system is a NFT type system. Check it out from the link in my signature.

I have nothing useful to contribute yet
but I am going to build an NFT soon !
I have the same questions you have but also wonder about filtration... is a 5 gallon bucket of gravel enough to trap the solids before the water heads through the NFT system ?

8" PVC is way over the top for NFT, and very expensive
I use 90mm (thats about 4") because its cheap and more than big enough. I do have a section of 150mm but in retrospect that was a waste of money.
You dont need much water in the bottom, 5-10mm, but I dont know what is "best practice"
net pots either need to come into contact with the water or as someone else suggested here put a wick to reach from the bottom of the pot to the water so that water can come up to the pot , then the roots will come down to find the water.
I would suggest a filter between the fishtank and the NFT so that fish poop and other solids dont stick to the plant root and choke them of 02.

I have access to some free 8" so for me that is cheaper than 4"
I also just finished building a sump/filter so I'm all set for that! (Will post pics soon as I find the camera cord....)

It's good to confirm the pots have to touch the water, I'm definably still in the planning stages as far as GB vs NFT.

I'm off to read some more!

joeygrob - I'll try to get pictures of my filter up soon, but I imagine it's going to depend on you water flow and fish load.

Its only cheap if you also get the fittings to go with it. End caps for 8" pvc are expensive on their own.

2 gallon paint buckets from Home Depot are $2-$3 each and seal up the ends nicely with large hose clamps. I got my 8" pipes from a guy very cheap... that's why I went with that size. My net pots are not touching the water below and the plants are doing pretty well. I do have to pour water (out of the FT) in the middle of the day when the sun is directly overhead. I have little roots poking out of the gravel now reaching for the water below. My theory is that the tubes are very humid inside with the constant flow of water so the gravel stays moist.

BTW... on the 8" pipe, use a 2 3/4 hole saw for the 3" net pots. The 3" hole saw made the holes a little too big given the curvature of the pipe.

Thanks!

I'm thinking about cheating at this point, maybe filling the pipe with 6" pots and setting it up to flood and drain, then it might be like a grow bed but I could easily trim the roots......
Does that make any sense at all?


Thanks,
Chance

No... NFT pipes/channels... require a constant flow... by definition...

Some members have tried media filled pipes.... either continous flow... or flood & drain... almost always with problems resulting from root blockage...

IMO... set them up without media... and continuous flow...

Having said that... Synaptoman utilises large media filled half pipes with flood & drain... but without net pots...

8" pipes are very large... and will require considerable volume of water, especially initially while the roots develope.... perhaps, if you can adjust it... less flow as the roots descend ....

Not sure what you're paying for the pipes... but did you compare pricing of standard NFT channels???

I'm not paying anything for the pipes, which is why I wanted to use them.
I can probably get some 4" pipe instead (100mm), but I hate to waste good materials.

I was thinking that I could avoid the problems of roots obstructing the GB by only having media in the baskets, then I could lift the basket and trim the roots...

Since my materials are free it might be worth a shot, but I might also need to setup a traditional NFT setup with 4" pipe to compare.

Thanks!
Chance

So my system is cycling.. I'm adding plants, and am about out of room and waiting waiting waiting..
I'm planning my next trick, an NFT setup running on a pump out of the sump tank to 10 foot sections of guttering on the wall with netpots and hydroton..
I found a great price tonight on 4" wide by 3" deep box gutter, and wondered if you thought 3" deep was enough, or should I try and use smaller 2.5-3" netpots on the 3 inch side.. I plan on growing bibb and other lettuces !!

Thanks so much for your help,
Joey

3" is plenty deep enough for NFT... especially lettuce...

4" x 3"... would be a pretty close to a standard hydro channel...

Great !! They even have a "contractors pack" - 10 sticks 10' each for $100 at Lowes !