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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 18th, '17, 15:56 
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Yavimaya wrote:
lol constant flow or constant flood? we already have those for other things....

how about shallow water culture..... like we have called it here in the past....? :smug:
You're missing the point of the post Yavi... It's simply about making people aware that the second design in the pic is not NFT... to help avoid confusion when they are discussing their system, or planned system, with others.

But, while we're here and discussing labels, what design do we already attribute the term Constant Flow to?... That’s always been a grey area for me.

I must admit, in all the years I’ve been on this forum, I don’t recall ever seeing the term Shallow Water Culture (SWC) before, but I’ll take your word on it. While I can see how the term SWC could be applied to the second design in the pic, and I’m aware the terms Constant Flow and Constant Flood are used to describe other designs, how is it that the round pipe design couldn’t fall under either of those descriptions?... If for no other reason than to avoid complicating things, especially for newbies, by adding yet another design label.

For many years I've sold hydroponic systems as per the design description for the second pic, except with the water inlet located at the very bottom of the end cap on the inlet end of the pipe, so when the pump turns off the water drains back out of the pipe via what was the inlet. This is definitely Flood & Drain, yeh?... So if I then place the water inlet high up in the cap and run the pump continuously, I’ve removed the Drain aspect, but still have the Flood aspect, and it’s both Flowing and Flooded 24/7... So why can it not then be referred to as either Constant Flow, which is probably the most apt, or Constant Flood?

And while we’re questioning the terms or names used for systems, at what water depth would DWC become SWC?... and at what point then would SWC become NFT?

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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 18th, '17, 16:45 
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Told you this was going to become iffy :)

Media in round pipes is constant flood (Unless you F&D it)
Constant flood is DWC with media.
F&D is Constant flood and NFT
Continuous flow is vertical NFT.

The point at which these change is the air/water ratio. Well only IMHO. :lol:


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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 19th, '17, 01:35 
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Uh oh... I'm guilty... so since I used round tube this isn't NFT anymore? What about if I'm still only running a very slow amount of water through it and there is a slimey film on the inside of my tubes? My drain actually 90's at the end and then comes out the bottom, so there is no standing water in my tubes, but since I'm using pool noodles to hold my rockwool at a point where the rockwool can touch the water I do have to be mindful of how deep I set the pool noodles or they will block off flow and cause it to run up higher in the tubes.

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At what point is a very slow amount of water not NFT? I did just so happen to measure my water throughput of this "NOT-NFT" system last night...

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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 19th, '17, 07:41 
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It has nothing to do with the speed of the water it depends whether the roots are submerged. :)

I may as well put in the other two

aeroponics the water is misted onto the roots
wicking the water is drawn up to the media by capillary action

Personally I don't give a rats ass what you call it but I would really be pissed off if someone advertised NFT tubes and I got there and they were round. :lol:


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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 19th, '17, 12:39 
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Sleepe wrote:
Personally I don't give a rats ass what you call it but I would really be pissed off if someone advertised NFT tubes and I got there and they were round. :lol:
Yep, I don't give a flying fornication what it's called either, although it would be good if everyone was on the same page as far as a name was concerned.

What really gets my goat though, are the Youtube experts telling people how to build these "NFT" systems and the Gumtree gurus flogging them, some even going as far as stating in their ad's that they provide free "expert advice and instruction" on how best to operate these "NFT" systems.

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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 19th, '17, 16:08 
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A quote from that book I listed earlier.

"Unscrupulous adventurers attempt-ted to cash in’ on the discovery by selling useless equipment at fantastic prices to the ignorant or credulous."

This was referring to the late 1920's (I think). Snake oil salesmen have been around since the year dot; at least if some people do a little research (available now online) they won't get shafted as easily.

There again most people are naturally credulous. :lol:


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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 19th, '17, 21:08 
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"Wow" how the post has developed over the last couple of days while my internet was down.


"Ah, yes... the old TMF&DCFT system... but who knows, that's probably wrong. :roll:"at least we're on the way to having a correct name for it.


"I would use 100mm DWV, it’s almost exactly twice the price (at the big red & green sheds here in Perth at least), but..."

I got it for free and so I'll need to paint it to block out the light, modify the 50 mm net cup collars and I've got short spans of just 5'.


"Also... Are you planning this addition to your system so there are more plants removing Nitrate and other nutrients?" Yes.

I was thinking of adding another bath tub but the space requirement was too much between the other GB and glass house. I figured if I could circumnavigate the system with two rows of tubes I'd get 50 lineal feet @ 12" spacings 50% offset I'd 'be able to house net pots of low growing plants like strawberries mixed salad etc.

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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 22nd, '17, 06:54 
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What are the fundamentals of setting up an NFT system?

http://www.hydroponics.com.au/what-are- ... ft-system/

What factors are important in setting up an efficient NFT system for different types of plants?
Answer
Nutrient film technique (NFT) is a recirculating hydroponic system where nutrient solution flows down a set of channels (also known as gullies). The solution is pumped from a holding tank, through irrigators at the top of every sloping channel and the run-off from the bottom of the channels is returned to the tank. A simple fundamental layout is shown in Figure 1. (Note that this schematic has the pump above the tank, in which case it would need to be a self-priming pump. Usually the pump would either be external to the bottom of the tank—to give a positive suction head; or else, a submersible pump within the tank.)
Figure 1. Simplified schematic for an NFT system for tomatoes.
Figure 1. Simplified schematic for an NFT system for tomatoes.
NFT principles
Plant roots require oxygen in order to respire, that is, to make use of the energy input from photosynthesis. In the process of respiration, plant cells take in oxygen and release carbon dioxide. If roots cannot respire (often because they are waterlogged with water that has run out of dissolved oxygen), they will die.
The thing that is unique about NFT is the fundamental requirement that the plant roots are in a flowing thin film of nutrient solution. The impact of the thin film is twofold. Firstly, some of the roots in the channel will be directly in contact with the air. Secondly, when dissolved oxygen in the water is taken up by the submerged plant roots, this oxygen can be replaced by absorption through the large surface area of thin water film.
A well designed NFT system will never have a problem with a lack of oxygen in the root zone. Bad design will eventually lead to plants dying from lack of oxygen, often resulting in total loss of the crop.
By its nature, a basic principle of NFT is that it is a ‘closed’ recirculating system.
History
The technique was first developed in the 1960s as a research tool by Dutch researcher H.C.M. de Stigter of the Plant Physiological Research Centre. The commercial potential of this technique was recognised and its further development was led by Dr Allen Cooper of the Glasshouse Crops Research Institute (GCRI) in the UK. NFT development continued over the 1970s and a number of large-scale UK commercial glasshouse growers converted completely to NFT, mainly growing tomatoes and lettuce. However, almost all have now changed to media-based systems, mostly using rockwool or cocopeat.
Since then the technique has spread across the world, especially in hobby-sized systems. However, commercially it is mainly used to grow short-term vegetative crops such as lettuce, herbs and Asian greens. Of commercial hydroponics (soilless culture) around the world, NFT contributes probably only about 3% of the total area, by far the largest proportion of which is in Australia using NFT channels on tables and mobile gully systems.
Channel design
Shape
The basic requirement is that the shape of the cross-section of the channel should allow the solution flow to have a basically flat profile. Consequently, the worst profile is a circular tube; although growers who have nursery channels to get lettuce started before transplanting will sometimes use small circular pipes).
The other aspect of shape is the width of channel. This needs to allow for the size of the root mat of the mature crop intended to be grown in the channel. Typical widths are: 100mm (4 inch) for short-term crops such as lettuce and herbs, etc; 150mm (6 inch) for longer term, but relatively small plants such as strawberries; 200mm (8 inch) or preferably wider, for longer term large crops such as tomatoes. To ensure that water flow contacts small young plants, specialist channel profiles have a dip or small ribs running down the base. For large channels, a narrow strip of capillary matting can be placed across the channel under the new plant.
Figure 2. Australian NFT tables for growing lettuce, herbs and Asian greens at a convenient working height. Channels are 100mm (4 inch) wide and 50mm (2 inch) high. There are two 6m (20 ft) lengths sloping from each end to a central return pipe. For wide lettuce such as ‘iceberg’, there are about five channels per table up to eight to 10 channels for smaller plants as shown here.
Figure 2. Australian NFT tables for growing lettuce, herbs and Asian greens at a convenient working height. Channels are 100mm (4 inch) wide and 50mm (2 inch) high. There are two 6m (20 ft) lengths sloping from each end to a central return pipe. For wide lettuce such as ‘iceberg’, there are about five channels per table up to eight to 10 channels for smaller plants as shown here.
Slope
The GCRI recommendations were initially for a minimum slope of 1 in 100 down the channel, later increased to 1 in 75. Both of these were intended for layflat plastic channels placed on accurately smoothed concrete floors. In Australia, for rigid channels placed as tables on supports we recommend 1 in 40 (or 2.5%) to allow for some sagging between the supports. A general principle is that ‘dead spots’ are to be avoided.
Length
Length interacts with slope, but for a slope of 1 in 40 the usual maximum length recommended is 12m (40ft). For flatter slopes, it is recommended to have a maximum length of only 6m (20 ft).
Layout
In Australia, the growing of hydroponic lettuce, herbs and Asian greens is usually done on tables at a convenient working height as shown in Figure 2. The produce is often sold as living plants.
Flow rate
When using wide channels to grow large plants such as tomatoes, a flow rate of up to 2 litres per minute per channel is used. For the 100mm-wide channels growing much smaller plants, a flow rate of about 0.5 litres per minute per channel is used. For steeper slopes, a higher flow rate may be needed. For insurance against blockages, two irrigators are often put into the top of each channel.
Tank size
The working capacity of the tank determines how much nutrient solution is held per plant. The smaller the volume of solution held per plant, the more unstable the system can become. For systems without automatic pH and EC control, obviously these properties can be affected. However, other major properties to change significantly, whether there is automatic control or not, are solution temperature and nutrient balance, which can be the unrecognised cause of problems. For example, a downside to pH control is that it can add substantial amounts of acid and hence significantly change the solution nutrient balance.
Put another way—to save money by buying a small tank can come back to bite you through solution instability. For small plant systems I recommend 0.5 litre, or preferably more, per plant working capacity; and for large plants, at least 2 litre per plant.
Bad design
Here is an example of what can happen if the NFT design is bad:
A multi-million dollar hydroponic strawberry investment scheme set up NFT systems as follows: 100mm-wide lettuce channels (better at 150mm), length of channels = 30m (should have been no more than 12m), slope = flat (should have been nearer 1 in 40).
My prognosis was that as the plants matured, especially once they started fruiting, the root oxygen demand would increase, using up the oxygen in the solution. The last plants in the channels would then get oxygen starvation and die, soon leading to the death of all the plants in that system. This is what predictably happened. The company blamed it on herbicide sabotage, but it was simply appallingly bad design. Another poor aspect of their design was that the channels were only raised to knee height, thus negating the major benefit of having a convenient working height. Ω
PH&G October 2014 / Issue 148

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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 22nd, '17, 16:18 
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>> solution flows down a set of channels (also known as gullies).

the moot points is it is a technique *NOT* a specific configuration.
Whether it is done with rectangular channel cross sections of larger flat 'corrugated' surfaces
(that some commercial setups have used) is not really the issue.

Bit like saying Aquaponics is only Aquaponics if you use clay balls.....
(this conversation has happened before regarding dutch/bato buckets).

However in agreement with Yav, I definitely feel that SWC (shallow water culture) is a better alternative description for those style of PVC pipes. Because the intent is for the pipes to run some depth of water not a film.
The method is also consistent with DWC which in many respects is very smilar to what SWC people are doing anyway.

But if its a thin film of water its a thin film of water.

>> and at what point then would SWC become NFT?

that question is already answered in the 'technique' and an earlier post.

If the pump stops in an NFT then roots dry out.
In a SWC pumps flows are potentially less significant.

Constant Flow would be a sub-category because by design (retaining water) you can run a SWC or a DWC on a timer....

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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 22nd, '17, 17:10 
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dlf_perth wrote:
>> solution flows down a set of channels (also known as gullies).

the moot points is it is a technique *NOT* a specific configuration.
Whether it is done with rectangular channel cross sections of larger flat 'corrugated' surfaces
(that some commercial setups have used) is not really the issue.

Bit like saying Aquaponics is only Aquaponics if you use clay balls.....
(this conversation has happened before regarding dutch/bato buckets).

However in agreement with Yav, I definitely feel that SWC (shallow water culture) is a better alternative description for those style of PVC pipes. Because the intent is for the pipes to run some depth of water not a film.
The method is also consistent with DWC which in many respects is very smilar to what SWC people are doing anyway.

But if its a thin film of water its a thin film of water.

>> and at what point then would SWC become NFT?

that question is already answered in the 'technique' and an earlier post.

If the pump stops in an NFT then roots dry out.
In a SWC pumps flows are potentially less significant.

Constant Flow would be a sub-category because by design (retaining water) you can run a SWC or a DWC on a timer....


Can we get rid of the Constant Flow and Yav's humorous SWC? :lol:


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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 23rd, '17, 06:55 
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guess if they posted "doing something with round pipes" that should cover it....

that makes it a DSRP system, though following Pete suggests it should be more like DSRPWCF or DSRPWT.

Still liking SWC though Sleepe... but we have to wait until someone prominent in the AP says they have invented it (10 years ago) and it appears 20 years later in the next UVI/College/TAFE Course....
Though with the expansion of dodgy Online College courses it might happen sooner when they plagerize this thread :wave:

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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 23rd, '17, 07:33 
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People are constantly coming up with designs in round pipes its just as well they are not doing it continuously. :lol:
We already invented Continuous Flood to describe DWC with media as opposed to F&D.

Someone want to define the point at which SWC becomes DWC? :)


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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 23rd, '17, 08:45 
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DWC where the depth of water and size of container is not restrictive on the roots, and where aeration etc comes into play. Really talking depths of 200-300mm+ (ie. 8-12"+)

SWC is applicable to shallow systems where the roots are potentially constrained and/or the depth of water is not maintained at a level that allows 'free-ranging' roots. ie. roots may tend to matt or lie in one direction in contact with the container, typically associated with depths 50mm to 150mm/200mm.

** need a better term than 'free-ranging'. But it is quite evident where you get strands of roots in a DWC and matts of roots in a SWC in a pipe. 150mm-200mm is certainly plant dependent but reality is it is about right. Most advice around here with DWC deals with 'a depth of water', aertation implications (DO) and clean roots.

SWC (DSRP :D ) really have different set of issues - some of which got mentioned here earlier.
But mostly that the root matt becomes significant to the depth of water as plants develop.

personally I dont really care it really is too deep to be a NFT by definition and a bit too shallow to be a DWC in classic terms. So SWC seems to fit. Personally I am still voting for DSRP...

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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 23rd, '17, 09:06 
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>> This was referring to the late 1920's (I think). Snake oil salesmen have been around since the year dot; at least if some people do a little research (available now online) they won't get shafted as easily.

this made me smile in consideration of all the mis-information on the internet... some of it is so good it actually looks better and more palatable than the truth....

got to love those kitchen top systems that can feed a family............ need a special category for them....
SHAFTED comes to mind (Small Home Aquaponics with Fish Tank Exaggerated Deliberately)


Anyway while on my trip to Bunnings I might check out those circular NFT channels....
wonder if B will put the prices up now it is no longer just PVC pipe...
...need the sun to shine so I can go outside I think.....

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 Post subject: Re: NOT NFT!!!...
PostPosted: Sep 23rd, '17, 18:49 
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Actually I have just come in to a considerable fortune; all I have to do is remit a small amount of money and my bank details to some very important people. :)
I will be able to hire a number of experts to help me set up a new Aquaponics system with.

SWC
MWC
DWC
And not forgetting indeterminate tomatoes
FDWC

While the weather has turned a bit nasty again, I am sure the dams are getting filled and we can expect the Government to reduce our water charges. :)

Yabbies was trying to help forum members but these things always end up like this.

Anyway I hope you got your round NFT tubes at a good price before everyone catches on. :lol:


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