Backyard Aquaponics
A place to discuss aquaponics

here is the drawing

greets
frank

OK... certainly an interesting (and neat) concept Frank...

I still see potential flaws...

One : The height of the tank would make it extremely difficult to feed/harvest/observe your fish...

Two : Would the "overflow" extract the solids from the tank... perhaps dependant on the size/flowrate of the pump...

Three : Would the overflow from the "solids settling tank" be sufficient to create enough oxygenated flow to the NFT tubes....

Four : Would the growbed "drip" drain sufficiently to enable the pump to run continuously... (Or are you intending a "continuous flow", drip drain growbed)

If not then the system would probably have to be based on a timer....

My concern either way is what period of time would be taken between the first (top) NFT tube and the fill of the subsequent pipes and growbed, before returning to the pump/tank....

And whether the plant roots in the NFT pipes would dry out... also whether or not you could acheive an even "continuous flow" throughout the growbed... or whether, similarly, it may dry out in sections...

Five : Would the system acheive sufficient oxygenation....

I have doubts that the flow rate through both the NFT pipes and growbed would be sufficient to oxygenate the water sufficiently...

Six : The extraction of the solids, even allowing for subsequent manual distribution to the growbed may deprive the plants in the system of essential trace elements...

It has become a concensus, that the distribution of solids throughout the growbed assists in trace element supply to the plant roots...

I have doubts as to whether distributing them directly on top of the growbed (periodically) would acheive the desired results...

Even if delivered as a "worm" tea mix... the majority of the solids could remain on the growbed surface...drying out to form a surface layer that would further prevent any oxygen being pulled down through the bed

Especially as the inflow to the growbed is restricted to a single point at the end of the growbed and would be a very slow flow from the NFT...

I'm assuming the "solids" are removed periodically from the settling tank via a tap of some sort... raising some concerns as to how often this may be required and whether or not anaerobic conditions might develope....

If this were to become the case... it would rob the water flowing to the NFT (and subsequent components) of oxygen....

Seems rather labour intensive... in comparison to the set and (essentially) forget Chift Pist to growbed to sump (branch to NFT to sump) type model....

And IMHO it just doesn't offer any great benefits... while possibly having potential disadvantages, including potential "fatal" consequences to both fish and plants due to lack of oxygenation...

My other concern would be .. if the pump were to fail... nothing would flow to the NFT... which (from hydro experience) could result in plant death very quickly...

And possible saturation of the growbed.... obviously this is time dependant...

Of course .. you could just remove the solids/worm tea altogether and use them in compost or on a soil garden.... and just run the growbed as a DWC style with floating rafts....

Just grow lettuce and basil....

Still would have some concerns about oxygenation.... but it might work that way....if you could keep the flow up...

Ack!!!! Please shrink images down to medium size so we don't have to scroll sideways to read each line of an entire page of posts!

Jeez, Rupert, you sure are a man hard to please

Ii am confident you, with all your experience, can answer most if not all of your own objections

Let's first take into account that this is a setup intended for a vertical stack of NFT channels due to lack of horizontal space.
The same solution could be applied in a "normal" situation where there would be no need to lift up the fish tank.
That would take care of most of your objections.

But I will comply:

The tank top highest level in my drawing is at ca. 2 meters.
This is determined by the highest NFT gutter.
You will need a step or ladder to take care of the plants in this gutter.
The same ladder/step will be handy to "feed/harvest/observe your fish".
Should I have drawn a ladder/step in the drawing? I don't think so: this solution is so obvious. Nothing "extremely difficult".
Quite the contrary: harvesting would become exceptionally easy: just open the (wide, not drawn) fish tank drain valve and the fish will be swept into the container you hold beneath it. Child's play.

That would be entirely dependent on pump flow rate as you state. That is a question of dimensioning pumps and pipes. A "bigger" pump will ensure fast flow and efficient solids removal. It would surely beat any system of periodical draining (which by the way would waste a lot of water).

It would not need to, because if you carefully read the concept, you will have understood that even in the NFT tubes ebb and flow (= periodical aeration) is created.

There is no growbed drain. All there is is a compartment in which the pump is located. The pump is controlled by level switches, so it would not run continuously. It is not intended to run continuously. It is intended to provoke an ebb and flow effect. Of course fast enough water access to the pump compartment must be ensured. This is easy: make the compartment big enough and the connecting faces permeable or else lay some drain pipes along the bottom of the growbed leading to the pump compartment.

already answered: ebb and flow in all plant holding elements

The "even allowing for manual distribution" is contradictory to the whole sentence.
Nowhere is stated that they have to be "distributed directly on top of the growbed". One could inject the solids at need into the water after the last NFT drain just before the growbed.
The "inflow of the growbed" being "limited to a single point" is for drawing simplicity's sake. No limits there.
The solids can be removed either periodically or continuously as I believe I have stated (but I might not have done so).
Not labor intensive at all, quite the contrary: possibly fully automatic, unless you would decide otherwise. Certainly not more labor intensive as any other system except for climbing a ladder every now and then, which is a consequence of a vertical setup. I wouldn't know where any extra labor would be required.
Less possible fatal consequences at least for the fish. And TMHO also for the plants (unless you would point out where).
"If the pump were to fail... "
any system, especially an NFT system would suffer.
This can be limited in this (as in any NFT) system by drilling the drain hole in the overflow pipe a little above lowest level: that would ensure a little water stays in the NFT gutters.
Saturation of the growbed can only occur in case of pump or level detection failure.
Still your fish would swim in maximum water, always at the same level, and, if you follow the directions mentioned above, a little water would remain in the NFT gutters.
But NO system is absolutely fail proof. In that it doesn't differ from other systems
I think this setup comes quite close (closer?) to "fail proof".

greetings

Frank

Here is a very simple quick diagram that takes this stuff into account.



Key points that are nice is that the solids go directly to a flood and drain grow bed without any extra work. The pump is after the grow bed so is kept in a cleaner environment which is always good for pumps. The flood and drain grow bed provides good aeration for the system as well as the solids filtration and bio-filtration needed and a handy place to grow a few larger plants. The NFT troughs can be fed, plumbed, and supported however you like. This diagram doesn't show exact layout, just the general idea. The grow bed only needs be a little lower than the water level in the fish tank (which can be on the ground.) The grow bed only needs to be a few inches above the top of the sump tank. Depending on the shapes of the containers used, this could work out quite neatly.

The fish tank could overflow by simple venturi drain into a grow bed which could drain by auto siphon into a sump tank which would have a pump running all the time feeding the nft tubes as well as back into the fish tank. The NFT tubes could drain back to the fish tank, grow bed or sump tank. So long as there is enough flow into the fish tank to keep it aerated and circulating the solids out as well as flow into the NFT troughs then all should be well with one pump though a two pump system might provide more fail safe.

Sump just needs to be big enough to handle the level fluctuations of the grow bed flood and drain as well as the flow for the NFT plus a little bit so the pump doesn't run dry though I always say a bigger sump is a good idea so that you can also install a float type top up valve below the "normal" low water mark to take care of topping up for you.

Truth is, I think I already suggested exactly this early on in the thread, simply adding a gravel filled grow bed next to the fish tank/over the sump in the original design.

TCL... agreed... you've not only basically drawn my proposed "mega" system... but a schematic of almost every system that anyone has ever implemented....with the use of a second pump in the sump to supply the NFT

Frank....

I'm not that thick as to have not assumed (whether drawn or not) that you would need a ladder to access the fish tank for the purposes of feeding/harvesting/water testing etc

I merely pointed out that the height made such tasks difficult... and a potential OH&S issue from slipping.... particularly for anyone who may be more elderly/frailer...

At two meters... climbing/decending a ladder with a bucket of feed or harvested plants may present some difficulty or danger to some people...similarly when re-planting/cleaning the NFT pipes



But not "raising" the tank limits the amount of NFT pipes that could be used... negating any benefit over just having them horizontally.....

I still have some doubt as to whether an inflow, even with a good flow rate, would be sufficient to "lift" solids up an overflow pipe as drawn...

[quote=Frank"]It would not need to, because if you carefully read the concept, you will have understood that even in the NFT tubes ebb and flow (= periodical aeration) is created.[/quote]

Frank, I wouldn't call the overflow to a cascading series of NFT... an "ebb and flow" system.... it's more of a "trickle" flow from one pipe to the next... and with the period switching/pumping... not even a continuous flow as NFT normally is and IMO must be....

Unless the pipes are filled with a media, which would retain some moisture... then I foresee the plants potentially becoming too dry....I have noted the suggestion that the overflow could be drilled at a level such that a "little" water remained in the tube...

If the pipes are filled with media... even hydrotron... then there are issues as regards to weight and support... and blockage/overflow and eventual problems of access (even with a ladder) to clean the extensive root structures that inevitablly develope...

Inevitablly a blockage will occur IMHO... resulting in an overflow from the blocked section of NFT piping.... and subsequent loss of water... perhaps substantial amounts of water if it occurs when noone is present for a length of time...

With the "solids settler" merely supplied by "overflow" and the NFT supplied by the same means.... I can't see that any meaningful oxygenation is occuring... nor do I see any occuring through the NFT "trickle" sequence ...



If it assumed that the growbed is filled with media... then I believe the growbed will remain too wet and become stagnant/anaerobic...

If it is a DWC style growbed ... with a floating raft... then while such a system can be highly successful..... it is totally dependant on a continuous, fast flow of water to provide sufficient oxygenation for the plant growth....

I don't see these conditions being met by a trickle flow via the NFT pipes...

The only point where any real oxygenation occurs is when the water is returned to the fish tank... would this be sufficient.... possibly.... if the lower growbed wasn't in fact removing oxygen as it appears could occur....

A constant flow rate could alleviate this .... but that's not what the design acheives...



Well yes you could..... what with another pump/timer... or manually/periodically....

But would injecting solids (which may have been sitting, drying and decomposing) into a slow moving, periodically pumped, low oxygen (assumed) growbed be beneficial or detremental....

IMHO..... I think it could be highly detremental in terms of oxygen depravation, anaerobic developeement...



Without knowing the specific methology of the level detection switches... I still foresee the likelyhood of any such switch that might be exposed to the actual system water becoming coated with bio-film and potentially failing...

Especially if they are located in a growbed that may develope anaerobic conditions and algael growth...



Well yes.... but it's not exactly a selective way of harvesting... you have little control as to which or how many fish may be "swept" into the container....

And how much water may be drawn from the system before any fish are actually "swept" into the container... or onto the floor...

And what do you do with the now excess water... pump it back into the fish tank or growbed... with another pump.... broom it out the door or down a drain hole... and top up the tank.....

And what about any excess fish that may have been harvested... potentially all the smaller fish may have been swept into the container (or onto the floor)... before any fish of "edible/harvestable" size....

Carry them over a slippery wet floor in a bucket and climb a slippery wet 2m ladder with a bucket full of splashing fish....

And what sort of stress levels would this place on the fish....

I'm sure that some of the obstacles can be overcome Frank....

ie. heavily oxygenating the fish tank with airstones... airstones in the bottom growbed....

Lifting the solids with an airstone in the fish tank overflow pipe... ala an airlift....

etc, etc....

I just think it's simpler and IMHO more efficient to run a Chift Pist system and filter the solids through a "flood and drain" growbed back to the sump.... with a second pump to supply the nft pipes....

Perhaps Frank you could review Gnash's first system and KEII system threads... both have tried essentially this idea.... and both have found (some) issues that I've raised...

Particularly blockages with root growth...

Neither of them, however, have employed a slow fill, slow moving "un-oxygenated" growbed such as your design...

And I think what succes or failures they had directly related to oxygenation issues..

could you please try and take a more positive approach, Rupert?

a judge is supposed to look at both positive and negative before judging
you seem to go digging for possible faults while omitting to try and solve them.

and you seem not to have understood at all how this system works.

The key item is the solids settling tank.

there are two ways to remove the solids: through the bottom or over the rim of the fish tank
I propose to do this over the rim, as you have to pump up the water anyway to the upper NFT (if in an NFT system)
Same goes for any system, whether NFT or not: you have to pump the water to the highest point in your setup.
The drawing shows an NFT system since that is the subject of this thread, but I can easily adapt it for any other setup.

The solids are taking a free ride with the water if the speed is adequate:
solids are not lifted by anything else but the water speed in the standing pipe
That goes for any system
So the pump flow and the pipe dimensioning must ensure this
that goes for any system
so you must choose a pump that ensures adequate flow and dimension your pipe so this flow is transposed in adequate speed
that goes for any system, tank on the ground, tank lifted up, or tank buried. Pump in tank, pump outside tank, you name it.

I prefer above ground tanks for several reasons:
1. it allows you to take the pump out of the tank
2. it allows you to work in an overflow system
this guarantees constant water level for the fish
this eliminates the risk of the tank draining or overflowing in case anything goes wrong
if well designed it also completely eliminates the risk of the growbed overflowing in case anything goes wrong
3. all parts of the system are readily accessible, most are at working height.
4. the pump only pumps clean, filtered water.

aeration for the fish:
At normal densities for AP, aeration obtained by the flow of a pump of minimal design can be expected to be adequate, especially if the water flows sideways into the tank as shown on the drawing. This will create an eddy, with the extra advantage of gathering the solids in the bottom center of the tank for faster removal.
If you would wish to further enhance this removal of solids, just take the inflowing pipe back to the bottom of the tank and have the inflow there.
If you do this, don't forget to put an open tee on the top part of the pump exit pipe else you will create a siphon when the pump is stopped.
You can also divide the flow between an upper and a lower exit.

Coming to think of it, this system allows for much higher densities thanks to the solids settling tank and worm bin (fish tank lifted of not), which is one of the drawbacks of AP: you need a lot of space for plants if you want to raise some fish because you must dispose of the nutrients.
The solids settling tank quickly evacuates the solids from the fish tank where they are harmful to the fish to the settling tank where they are not.
From there, you can choose to either send them to the growbed(s) for vegetable production or to the worm bin for animal protein production for your fish or chickens.
Very flexible, and adaptable to the growth of your fish and to partial or total harvesting of either fish or vegetables.

At higher densities, you need a bigger pump for faster recirculation.
Having a second overflow on the solids settling tank draining directly to the pump compartment or growbed distribution pipe allows for adjustable flow to both the NFT and the growbed(s) or directly to the pump compartment if one of both overflows is adjustable. More flexibility. KISS principle on all parts.

At higher densities, I would drop some floating beads under a screen in the solids settling tank to also eliminate floating debris and ensure nitrification in all circumstances even if recirculation is not over the growbeds (I have calculated that you need 5 l of beads per m³ of fish tank at a fish density of 100 kg/m³ at a feed rate of 1.5% = 1.5 kg/day/m³).
I tried to enclose the excel filter biomedia calculator but that seems to have failed. Please instruct me.

Plant root aeration is ensured not by the water (which might be O2 poor depending on settling tank draining frequency) but by ebb and flow in both NFT and growbed(s) as already explained.
And it is not a "trickle flow".
and it is not slow either:
each time the pump starts the gutters are quickly filled to overflow. If you want to limit flow in the gutters, put overflows on both sides of the gutters.
Each time the pump is stopped, the gutters start to drain.
Draining speed is determined by drain hole size and number.
Draining height is determined by drain hole position.
Aeration is ensured each ebb cycle.
Flow cycle aerates the water.
ebb and flow frequency is determined either by growbed size and pump capacity if regulated by level switches or can be regulated by a timer.

You don't have to fill the gutters with media but you can.
You could also put the plants in pots filled with media, then put them in the gutters.
Easy to do, the plants have growing support, easy to take out, easy to harvest, easy to clean the gutters should that be necessary.
The combination of all the above would reduce clogging to the utmost minimum if not completely if you remember to cover up unused holes to avoid algae growth.
No blocking, no "subsequent loss of water" at all (which would not get lost anyway -don't know where you fished this idea- : even in case of -extremely unlikely- blocking, any blocking, partial or not, would drain the water back to the growbed(s).

the worm bed could be replaced partially or completely by a duckweed tank if you don't like worms.
I have not drawn the duckweed tank.

I have adapted the drawing by lifting the bottom of the solids settling tank up a bit.
Now solids removal and injection in the growbed(s) and/or worm bin and/or duckweed tank can be continuous
I have also added most items mentioned in this post.

I have no idea why you would want to criticize level switches in particular and at this moment: NO system is absolutely fail proof, not even a siphon.
The type of level switch (washing machine membrane switches) I have proposed is particularly adapted to the situation, readily available, cheap, extremely reliable, scroungeable, and will work under better conditions than in a washing machine since where it is located all water is filtered.
How often have you seen your washing machine or dishwasher spilling it's water on the kitchen or bathroom floor?
If you are not convinced, you can position the switch anywhere on the opposite side of the inflow of the growbed where algae growth and clogging are extremely unlikely to ever happen.

You know my opinion on air stones and airlift pumps: I think they suck. But that is explained in another thread.

finally, about safety:
aren't you dramatizing a tiny bit?
the ladder/step needed is not 2 m but max. 1 m high. But it could be much higher too which would allow for even more NFT gutters.

But I can see your point, so I have adapted the drawing to make the setup as child and senior safe as possible.
I'm sure you can imagine a safety brake on the ladder wheels.
I could have added a warning sign saying: under 16 and over 50 prohibited, but that would seem a bit ridiculous

Now I like criticism and skepticism: they force me to make my brain work.
I like the "worst case" approach.
Keeps me awake.
I thank you for that.

but TMHO you have been spending a good deal of time just sifting mosquito's (a dutch saying) (meant as a joke)

friendly greetings

frank

This is a hard thread to read so I may have skipped some. Like the picture, but hard to stand on a ladder and drink beer while watching the fishies. But if you put a window in the side thats okay. And I imagine the gutters are not on top of each other but are staggered. Always wanted to build one of these so I'll keep looking in on your progress. There is a great vertical system in the forum but not sure who owns it.

I reckon it would run quite well on an airlift pump

JUST KIDDING

Rupe is just pointing out difficulties involved with NFT and AP. He does this in every NFT/DWC thread, due to people having a lot of trouble with these types of systems in the past. Its information sharing

I like your drawing, and it should work pretty well - you have most of the problems sorted, just dont use plants like tomatoes that block up the pipes, put them in the growbed.

Give it a rest please Frank.... I'm not being negative ... in terms of investing any "emotional" input to my reply...

You asked for comments on the proposed design....

I said at the outset that it was an interesting and neat concept.... my judgements that followed were in the "vein" of looking at possible faults or points of failure...

And questioning whether or not certain aspects might work... either optimally, partially or be prone IMO to failure.....

The "critique" was offered in that spirit.... please don't personalise an arguement/critique that may not be what you want to hear... it's becoming tiresome.

As to "omitting to try and solve them".... your statement is completely incorrect Frank....

I offered my opinion as to what I thought was a better, and proven alternative (Chift Pist>growbed>sump>NFT>tank....

And gave substantive reasons as to any points I raised/queried.... or asked the "retorical" question... "would it..."....

Always couched within the parameters of "in my opinion" (IMO)....

I still have some doubts as to whether the standpipe/overflow from the tank to the solids settler will remove solids... as it is presented...by sheer flow alone when the pump kicks in.... an operation that is, or was at the time... not presented as a continuous operation....

And offered an alternative solution of the standard double pipe venturi Chift Pist arrangement used extensively..... or an airstone assisted airlift....

Obviously our respective definitions of "ebb and flow" differ greatly... as perhaps does (from my hydroponics background) our definitions of NFT .... filling a pipe... that then drains to another pipe... isn't what I'd call "ebb and flow".... but I'll go with your definiton...

The diagram showed the top NFT pipe being "filled" by the overflow from the solids setller... an operation that would only occur when the pump from the growbed/level actuators is in operation... causing an overflow from the fish tank to the solids setller... that overflows....

As this wasn't presented as a continuous operation... ie... it was dependant on a time interval, when the level switchs activated...

Then to me the NFT system was only ever filled (flowed) when the pump was in operation... and then trickled... gushed if you want ... to the next pipe etc...eventually draining (ebbing) completely ... granted (as noted) to the level of the outlet...

My query was ... would this eventuate in sufficient oxygenation of the root zone... and/or would the roots either have sufficient time to dry or dry out too much...

The volume in the NFT pipe is relatively small... but essentially dictates the frequency of the pumping cycle.... without knowing the "relative" levels that the flow switches may be set at... it is difficult to determine the frequency of pump cycles...

But ... given that the bottom growbed essentially may contain a "relatively" significant volume of water... I queried whether or not the flow from the NFT would be sufficient to oxygenate the water in the growbed... a point that still concerns me...

Other than that .. the only other point of oxygenation was at the point of water return to the fish tank....

What volumes and % tank turnover might be acheived each hour would depend on the volume of water exchanged from the growbed... and it's oxygen content...

I still don't understand the need to extract the solids... evidence seems to suggest they have a significantly beneficial affect on plant growth... at least in a "flood and drain" growbed system....other than the necessity to do so before the NFT component for reasons I gave...

For DWC floating raft... and/or NFT... solids may serve no real purpose and need to be extracted.... putting them back latter into a tank/sump/growbed.... just seems to serve no real purpose IMO.... and I believe could cause problems....

Why not just utilise a traditional "flood and drain" growbed before the NFT.. and grow veges in it...

The other concerns I raised about root cloggin and water channeling are all known and proven issues... and I raised them as such...

I still think it's a neat design Frank... might not be how I'd do it... and it may well work...

Personally, I don't see the benefits outweigh the (to me) disadvantages of Chift Pist... flood and drain growbeds and sump... with NFT as an add-on....

But I do understand that you are presenting an alternative to a media based growbed before NFT scenario Frank...

Build it Frank... and show us all just how successful it works out....

Should read ... Personally, I don't see the benefits outweigh the (to me) advantages of Chift Pist....


But the two ideas are I suppose fundamentally different in approach and design...and perhaps it's unfair to compare the two...

Chift Pist utilises a bottom drain, with a "venturi" type of lift for the solids removal.... and subsequent deposit of the solids into growbed(s) to benefit a wide range of vegetable types....

The design posted by Frank is designed to overflow to systems that require solids removal....

Not, as such a "flawed" concept... but IMO... just a limiting one in terms of utilisation....

I still stand by my concerns as to the removal of solids utilising an overflow pipe as shown...and to concerns regading oxygenation....

Even in DWC systems like that of UVI.... they rely on highly supplemented oxygenation prior to delivery of continuous fast flow water....

Even DWC style hydro (NFT) channels require the same..... whereas normal NFT relies on a constant "thin film"... and is usually oxygenated either in the nutrient delivery tanks and/or within the channel nutrient input... to supplement the "natural" oxygenation the root zone is exposed to by not being constantly submerged... ala DWC....

Regardless in normal NFT.... any extended period of pump failure, or pump inactivity... or even too slow a flow rate... can lead very quickly to plant death, or stunted growth...

please don't think I'm angry when all I do is fiercely defend my concept.
I am truly enjoying myself in each and every of these discussions as they sharpen my brain and in most cases confirm my ideas.

whenever one of these ideas is not confirmed, you all help me to avoid mistakes, which is the purpose of my posting my designs.
and which is undoubtedly the purpose of all of you.
... receive some help and try to give some back
So thanks, sincerely

But having to draw a child and senior safe ladder because you seem not to have thought of this simple solution...
well, it's just annoying.

and of course if you hold a can of beer in each hand and already have consumed a few, Ozzie...


is not offering a solution to the problem you point at, but discarding the whole concept


I truly am surprised that you do doubt this. It is a simple siphon.
Ever tried to siphon some debris off the bottom of an aquarium? It works perfectly.
You don't need a pump, as you have the most perfect free pump right there at your disposition, and it is a piston pump at that: gravity.
As long as you keep the exit of your tube below the level of the water, the air column on the aquarium surface will keep pushing the water through your tube. The lower you hold the tube, the bigger the pressure difference,the faster the water will flow, the easier you will suck up solids and even heavy stuff like sand or gravel from the bottom of the aquarium.
Much as it might seem so, this energy is not really free: you have pumped the water into the aquarium in the first place, thus creating potential energy which you are now exploiting.

has absolutely nothing to do with the system: like with a siphon (it is a siphon), you can put your finger at any time on the tube"s exit and stop the flow, when you take away your finger again all action starts again including the removal of solids. Same happens when you start/stop the pump. Continuous or intermittent, a siphon will suck solids from the bottom at least as good as a pump, any pump as long as the flow is equal. The more water you pump into the tank, the faster it will try to run out (overflow).
Dimensioning the overflow pipe is important: if you over dimension you will lose speed, if you under dimension it might not be able to cope with the influx of water. But the margins are large, so don't worry. It is more difficult to get it wrong than right unless you would try to, which would be sabotage.

I am sorry, but I will exclude any venturi or air stone solutions as they gobble up energy. There simply is no need for them. A well designed siphon (not difficult) is perfect.

Except a venturi that works on gravity which would enhance aeration (and yes, I have a design for this).

But please at least stop pestering me with airlifts, you know my standpoint on them: and although I am grinning each time such a suggestion comes up, it is truly becoming tiring.

I don't think there are two definitions of ebb and flow: ebb is when the water recedes, flow is when the water comes up. Nothing simpler.

As for the definition of NFT, that is another question: maybe I should introduce (and I will from now on) another abbreviation: EFNFT, Ebb and Flow Nutrient Film Technique. It is similar to standard NFT, but with the additional element of alternating levels.

Of course a system's operation is always obvious for the designer, so I might have assumed it to be so for everybody. Sorry for that.

maybe you could agree to acknowledge that an ebb cycle would take care of root aeration, that would help.

next step is a bit more daring: would the flow cycle (after an ebb cycle) help in aerating the water? It would be win-win.

the "relative" levels in growbed and EFNFT gutters are independent from each other. Only the frequency will resemble. I say resemble, because by definition the effect of switching the pump on/off will be felt later in the growbeds than in the EFNFT gutters.


indeed, and that would be limiting while it should be relative to the aeration needs of the fish. that is why I added a second overflow to the pump compartment: to be able to use a bigger pump of which part of the flow would ensure necessary circulation whilst still removing solids in the same process. The extra energy consumed would mainly serve aeration if densities normal in AP are transgressed.


the beauty of the concept is that you don't have to put them back but you can if you wish. If you do, they will help plant growth. If you don't, they will serve another purpose: that of fattening juicy worms. you might not appreciate them, but your fish or chickens no doubt will.


that is an easy one: a growbed is heavy. It is impractical at that height. It is dangerous at that height (your argument!). It will cast a shadow on the other NFT channels.

Try to look at my design as not simply "neat", Rupert, try to be positive and approach it as bordering on perfect, but stay critical
It holds a set of new ideas, none of which you have succeeded in countering or rather of which I have succeeded in countering each of the objections so far.

greetings

frank

I am building it, Rupert, as explained to you in detail on another thread
But not in a vertical setup, as I don't have space limitations.

Greetings

Frank