Backyard Aquaponics
A place to discuss aquaponics

http://sketchup.google.com/3dwarehouse/ ... revstart=0

This is an in progress sketchup of my design. Right now I'm trying to figure out the logistics and have the sketchup perfected before I build the system.

The idea:
I will have 2 side by side systems completely symmetrical.
2 fish tanks comprised of 275g/1000l IBC's are sunken.
A pump feeds 2 connecting halfs of an IBC above the fish tanks with gravel and plants such as tomatoes and chilis.
These IBC halves will either be timed ebb/flow or continuous.
The IBC halves feed into 2 troughs that then feed into 2 more that come back to drain into the fish tanks.

Physics I'm in need of help with, what are the formulas to efficiently calculate what the level should be for each phase to utilize gravity and feed the system with only a pump initially feeding water with X head.

I didn't add the troughs to the sketchup because I need to calculate heights amount of water etc to determine how big they should be.. dont I? >.< Or should I design them to specific dimensions and that will affect what heights I need?

The reason I am splitting the small system into two narrow troughs instead of one wide trough is because it seems that there will be less stagnation.

Ideas I'm playing with:
Tilapia which I'll breed thus reducing an expense. ( I live in Phoenix Arizona and it gets very hot here so not worried about heating the water just of it getting too warm)
Maybe the occasional catfish
I am playing with the idea of having the first half of the incoming troughs be divided and filled with duckweed on top and below raising/breeding freshwater prawns and perhaps mussels?
The rest of the troughs will be home to all the happy greens that enjoy trough life and I'll intend on having fun learning what else I can successfully propagate in there.




Important questions. (I have run a tiny system before but you all know that means I'm extremely new )
My overall plan, what are the fatal mistakes I'm making that only someone with so little experience would overlook?
How do I approach the volume and height calculations?
Main concern I have is if the pumps fail and all the water drain out of the system since it's gravity fed what levels do I keep everything to prevent over flow? Are there techniques I haven't found yet?
I'm a novice so not looking to maximize stocking densities yet, I intend to build the system and grow from there to find out what densities work best for what I have. There isn't enough data in aquaponics to calculate efficiency levels from design, just approximations. (I've read at least this much haha)

I am very sorry but greatly appreciate anyone who has read this far and helps contribute to my unending education.

Kudos. A lot of people jump in with both feet without testing the water depths first!


The water volumes and levels etc are dependent on the media you intend to use in your GB. If your two "half" IBC GBs are actually only 400L of media which holds say 120 - 220L of water each, then you'll be drawing up to 440L of water from the FTs.

Although a lot of people say their IBC FT is 1000L most often its only got about 800-900L of water actually in it, so taking out up to half of the water might be a bit extreme for the fish. This is where the sump comes in handy. If your sump contains as much water as the GBs will require to flood to their appropriate level (plus a bit more for system losses, evaporation and transpiration between top ups) then you can have a CHIFT PIST (CHOP) system.

In your case though, with two 1000L IBC FTs, you can easily get by without a sump, with the water level dropping from 900L to 680L (less however much is in the pipework) at the peak of the GB flood (assumes a perfect flow between the two FTs which are perfectly level). This alleviates the need for the extra troughs and makes plumbing a lot more simple. "Simplicity is a key to success."



Assuming:
2 X 1000L IBC FT (filled to 900L, 100L ullage, each) = 1800L

You have 1800L of water which needs to pass through the filtration each hour. If you want to run continuous flow then you only need a 1800lph pump (or slightly larger to account for head loss). If you want to run timed flood and drain, say 15/45, then you're going to need a pump of at least 1800 / 0.25 = 7200lph (plus, for head loss)

To compute head loss, you need to know the height from the surface of the FT from where the water will be drawn to the maximum height through which the pump is required to deliver water; this is easily measured with a tape measure in most instances. You also need to account for pipe friction and the configuration of your plumbing; 90 degree bends impose substantially more resistance to flow (and hence head loss) than does a 45 degree elbow; the further water has to flow (linear distance) the more the losses. Unless you're having to be exact, in most BYAP projects pipe losses are not that significant that they have to be precisely computed, and in most cases they are substantially smaller than the losses associated with pumping vertically against gravity. Just have a look at the capacity vs. head graphs for each pump and select the pump which best suits your design.

Not understanding where all of your water is at any time, and thinking stocking density is dependent only on the volume of water in a system and ignoring the filtration capacity.

Draw a picture first, personally I use pencil and paper as I am faster at using these simple tools than I am at using computer based tools.

KISS. Let gravity be your friend not your enemy. With a pump in the FT, your biggest concern should be if the plumbing fails and water is not returning to the FT, you could pump the FT dry; this is easily overcome with a float switch to switch off the pump if there is an exceptionally low tide, changing the configuration of the pump intake to force the pump to lose suction in the event of an extremely low tide, or plinthing the pump off the bottom of the tank so it loses suction at extremely low tide (or a combination!)

The next concern is if the pump fails and this is your only source of oxygenation, what are you going to do? Do you have an air pump on a different power supply? Do you have a backup pump on a different power supply?

What are you trying to grow? Fish? Or plants? In my case I want the plants and veges, the fish are just an edible by-product. In this case, the stocking density is much lower and therefore has lower risk (or at least less adverse consequences in the event of realised risk events). If you're system is biased toward growing out the fish and the GBs full of veges and flowers are the by-product then you're going to push boundaries so you're going to need to be much more risk aware and have more complexity on your systems and more fail-safes. Again, KISS.

When the system is first installed and fully cycled, I'd not be adding any more than about 2kg (harvest weight) of fish in each of your systems because you only have about 800L of filtration in each. This limit seems quite severe, but later when the system is more mature and you have all the required safe-guards in place, you could push this density a LITTLE more.

You might consider redesigning the system to incorporate the troughs you mention as extra GBs and/or sumps? Or chop up another IBC to have 3 "half" IBC GBs with a full IBC FT and a "half" IBC sump? Or acquire another IBC and use this in the sump, then you could end up with something like:



If you've got two pumps on separate timers you could interlock them with some simple electrical relays and share the sump between your two symmetrical systems?

The options are too numerous, and I don't know any of the constraints you've got, like space, money etc. Think about the design some more and post your eventual concept and I'm sure someone will highlight any potential errors or omissions. It's easier to change a plan than it is to change the project after its built.


$0.02c

Oh where to start! btw worth more than 2 cents haha

Firstly I am implementing the troughs how I described, I just didn't put them in the sketchup until I knew the most efficient dimensions. Everything I put in the sketchup is to scale.

For priority it is for sure veges>Fish>Prawn>Mussels if I decide to go the described route.

So it seems to me like the best thing for me to do is design the troughs to the size I desire and then do calculations for density and the like from there. I'll get right on that and post the updated design.

Few quick questions hopefully answered while I'm adding to the design ^_^
1. I plan on connecting the tanks with bulkheads, are they pipe diameters that are best for a system of this size? In my hydroponic set up I use 1" piping but it should be 2" for more efficient water exchange and I'm wondering how large it should be for IBC's.
2. I know for the troughs there should only be an ever so slight incline so I guess I'll math that out when I do the dimensions. (1ft/32cm) depth okay for a trough or should I add 50%?
3. How come this community is so awesome? haha

The bigger the better. Eventually everything which comes into contact with AP water will end up with a coating of bio-film and smaller pipes might become clogged with debris and stray waste products. It seems people have been Uniseals quite effectively and these are available in quite large sizes. There is also a large bulkhead fitting (90mm / 3.5") which I have started to see more commonly in recent times.

One instance when bigger may not be necessarily better is if you are intending on using a SLO (solids lifting overflow); too narrow a diameter and the volumetric out-flow wont be sufficient and the tank will overflow, too large and there wont sufficient lifting-suction to pick up waste from the bottom the FT. The diameter is dependent on the flow of water into the tank, but SLOs are generally 50mm-90mm (2" - 3.5")

There is nothing wrong with level! A few millimetres of water left in the bottom for a short while will not cause any issues, except if it not mixed and drained out on a subsequent cycle.

As for depth, the generally accepted rule of thumb is that plants have feeder roots to about 30cm/12" so this is a "good" depth for growbeds. Insofar as filtration is concerned, some members here have depths between 15cm and 100cm (or more?) and all seem to be doing OK, although you're not going to plant a tall tree in only 15cm of light expanded clay!

I'm still not entirely sure where these troughs are going to fit into your system, so I'm curious to see the design and see how this fits in with your intentions. Please try to include any limits/limitations in the design you eventually post.

Because people who care, rock

Updated Sketchup so my idea is easier to see.

http://sketchup.google.com/3dwarehouse/ ... 12353bc431

The filter/growbeds feed into 2 troughs that are 30.5cm deep and 61cm wide also 244cm long. (I figured metric makes more sense so I may as well learn to visualize it, I already know the conversion but I want to be able to skip that step haha.

Each trough is connected to a return trough that is 488cm long same width and depth.

For the design I used 7.5cm piping which seems solid for the size of my beds.

This is my first attempt at using Sketchup so it's very rough but I have a good learning curve.

So for this system would a 5cm diameter SLO be a good segue to feed into the troughs that then utilizes 7.5cm piping for the return?

Yes making the whole thing level would be easier so I don't know why I'm trying to make it more complicated >.<'

Now my overview. FT=Tilapia ---> GB w/ Chili's cucumbers and the like ---> Trough (1st half propagating prawns and duckweed) second half and return trough for delicious greens on floating rafts. ---> FT

Once the troughs have been filled, they don't need to be accounted for in the water "usage" as their level should remain constant? If this is the case, then you could easily end up with something like:

Your tide in the FT will only be the amount which is pumped to the GBs, plus however much is in the piping (which is not going to be an insignificant amount) but you should be able to get this design working without requiring extra sumps etc.

Is the system going to be on a timer or continuous flow?

I just noticed I left off a trough too... but you should be able to visualise the concept?

Currently I have to GB's connected design wise so only one needs to drain into the troughs. My thinking is it is more GB filtration occurring prior to trough draining.
Also I was thinking CF for the GB's and the drain pipes just water fall straight down into the troughs for aeration.

I believe I solved my trough draining out concerns with the following, if the drain from the trough is angled upwards at the FT it will/should? only drain any excess of what I want my trough level to be at.
Secondary benefit, added drain height for water also increases aeration.

For the size of my system I don't think I'll need additional aeration unless I start playing with fish stocking density correct? If I do require more I have a 110l air compressor that was retired in a hydroponic set up that will aerate the heck out of the troughs. I would put it on a timer because a 112W compressor constant running would be another slice on my electric bill.

With the new setup I am going to buy my troughs like the FT and drop the FT a bit lower to adjust and in turn lower the FT stands to decrease head on the pump. So far it looks like I'll just need my extra hydro 2160 l/h pumps at 2m head height. The head will probably be 2.2m so a tiny bit more pump loss.

I'm going to play with sketchup and be back with another rendition addition + system maths

Okay right now as designed I am looking at a max of 8300 liters of water in the system. I did the math for the appropriate water levels and used the solids filter GB as taking up 70% of the mass of the tank and only calculated 30% water.

Is the Sketchup link okay or would people prefer screenshots? I'll do both this time and wait for opinions.

http://sketchup.google.com/3dwarehouse/ ... evstart=72

I think you'll need to elevate the troughs a bit more to allow the water to flow freely back to the FT. If you have the height I'd also consider having pumped the water to the highest point, the GBs, have this drop into the smaller troughs, which then drop into the large trough, which drops into the FT. You'd get aeration at every drop.



Personally I'd have the system "split-able" as much as possible to allow every different section to be isolated i.e. send water to one/both GBs at a time, the GBs distribute their water to one/both troughs at a time, the smaller troughs to return their water back to the FT bypassing the larger trough etc. This will make it a lot easier to perform system maintenance, add and remove components etc. You might also consider just being able to pump to the GBs without going through the troughs, so you'd need a return from the GBs to the FT.

(I see a lot more with a pencil and paper than I do with computerised drawing tools.)

Always : "Plan for the worst, expect the best."

As a continuous flood and/or continuous flow system, I think you have most of the basics there. I'd do a little more work with the plumbing; use "manifolds" for even distribution of water volume to the GBs and from the GBs to the smaller troughs. I wouldn't have one GB discharging into the other GB else you might the first GB will become completely clogged with solids and require cleaning, whilst the second does almost no "work" in comparison.

Remind me again that the troughs are just going to be constant height water for fingerlings, prawns etc, and not filled with media or other flow restrictors?

BTW: I have heard that mussels in AP systems can cause problems as they will spread everywhere including lodging in pipes, GBs and pumps. Do some careful research before including them because they might be hard to get rid of once they have been added.

I really like the idea for making the smaller troughs drop into the larger ones for yet more aeration!
I was actually thinking about the solids filtering aspect but I guess I removed too many ideas by minimizing the head height of the pump.
I'll just toss the idea of mussels since I was the only one in the family that enjoys them haha. What I want is for the smaller troughs to grow the duckweed and breed the large prawns then I'll use the long return trough for all the delicious greens.

Okay now I'll summarize to make sure I understand:
Elevate small troughs to add an extra drop for aeration.
**Just means I'll have to build a setup to support them instead of dig a hole but still a very worthwhile idea!**
"Splitable" ie each grow bed is being fill from fish tank to split the solids dispersion. Each grow bed then also drops into its own trough.
**I'll have to learn how to evenly distribute the water from the pump to each GB I'd rather have one strong pump with a back up on hand than use 2 pumps with back ups to minimize operating costs. Is 1 GB then feeding into each trough enough filtration?
Add a return line from the GB to the FT
**So a return line and probably a ball valve or something so I can just turn it whenever it was needed? Is this for easy maintenance, a back up, or more likely the overall versatility.**
**Also, I'll assume the return line from the first set of troughs to the FT is for the same reason as the GB to FT.**
The troughs are just filled with water, no media.
I like all the redundancy suggestions that give the systems much more flexibility!

Lastly I should resize the large trough return line (It was supposed to be 3" PVC but it measures a few inches too big I didn't check until the last minute) because the trough and FT are on the levels I needed the return line is just too large to properly display the idea. The end of the PVC is at the height I want the trough to be at so anything over that will force water to over flow into the FT and if something goes wrong it'll prevent it from draining and flooding the FT area... I should just assume you knew that but it helps me to type out the reasons, also so people can stop me and say, no, no no, doesn't work like that lol

Pump water up into a large diameter pipe (distribution manifold) which is above the water level of the FT but below the level of the GB. Tap smaller diameter risers into this large diameter pipe (include a ball valve). As the pump fills and pressurises the distribution manifold, the water level will rise against gravity; if the risers have the same resistance, all the risers will end up having (almost) equal flow through each (the discussions as to why it wont be precisely the same flow takes too long, so really close to uniform distribution is good enough for now)



The same principles can be used wherever you want to have uniform distribution by volume i.e. from the GBs to the small troughs. Locate a distribution manifold below the water level in the GB but above the water level in the small troughs.

I haven't done all the water flow modelling (you can do that?), but from the conversation thus far, you're going to have run constant flow / constant flood, so the system should be OK as long as all the water in the system passes sedately through the GB media on a regular basis (nominally once per hour). You're going to have to size your pump accordingly.

If the GBs aren't providing enough filtration, its because there are too many fish in the system! I'm not sure how much waste and ammonia prawns etc make compared to the different species of fish commonly found in AP systems?? It's going to be invaluable for you to do some research to ensure you have enough filtration volume to ensure that you can have all the animals you want in your system in your system!

I'd plumb this as an overflow. The principal is that if you shut the drains from the GB / delivery to the troughs that when the water level in the GBs get to critical height it automatically overflows to the FT. You don't want to make it so that you have to shut the delivery to the troughs and open a GB to FT return valve, because what if you only did the first part (shutting the delivery to the troughs) but forgot to open the GB to FT return valve? Try to incorporate as much bullet-proofing (idiot-proofing) in your design as possible.

There should be a way to get water from wherever it is in the system back to the FT (primary concern is to ensure fish have oxygenated water) and to any sump/storage tanks in secondary mode.

Plan for the worst case, hope for the best.



Scott

Mussels are fine in a system.... snails are a problem...

A distribution manifold is perfect, one more concept to add to my engineering database ^_^

All the water (4150Liters each pump) should pass through the system an hour? >.< lol damn I'm gonna have to get a bigger pump.

I don't intend to maximize my fish just my plants so you're right I shouldn't have to worry about not having enough filtration.

The reason I have my GB -> FT with a ball valve set up is because my whole system relies on one level overflowing to the next and don't think I would need yet another overflow from GB -> FT. I'm new so I could be gravely mistaken. I set it up so if I have to drain my GB's it's just a turn of the valve.

If aeration is the primary concern I was thinking about adding a fountain to each set of fish thanks for aesthetics and continuous aeration. My wife is an interior designer so I must make everything I do add aesthetic value as well but most of my ideas aren't incorporated into the sketchup, I have a hard enough time getting the functional ones built in it ^_^

Why is that Rupe?, I have some in the FT, not sure how they got there though.
Because they might block pipework?