Backyard Aquaponics
A place to discuss aquaponics

If you're going to run continuous flow and are considering the "rule of thumb" of pumping the water volume per hour, you might want to revisit the maths for your pipe sizing.

Use: v = Q/A

where v is velocity (keep it near 0.1 m/sec if you need to keep the majority of wastes suspended in the water flow), Q is the volumetric flow (m3/sec) and A is the area of the inside of the pipe (m2).

If you're continuously pumping a smaller volume of water, you might find a 90mm SLO won't lift the solids and a narrower pipe might be required; if you're using a larger pump and running flood and drain, 90mm might be suitable.

As for the risers from the CDM to the GBs, the same principles apply, I think 32mm will be too large, even for timed F&D, where 25mm or even 20mm should be able to keep up with the distribution to two GBs. A 90mm manifold is ok (in general, the larger the better), but you might be able to get away with something slightly smaller to save you acquiring a plethora of different size pipes and to prevent too many of the most dense solids from settling the manifold itself. As for tapping the risers into the manifold, see a picture made earlier for a couple of different methods:


If you're going to run continuous flow, this is one of those times when you might consider installing a siphon to periodically change the water level in the GBs (prevents anaerobic zones forming in the media).

(There's a difference between CF (continuous flow) and CF (constantly flooded), each has different design and management aspects).

Very good info, thanks. I thought 90mm would be too big but i kept reading 50mm as a bare minimum and always better to go a bit bigger (not too big)

I am having constant flood, i think anaerobic zones would be greatly reduced with an irrigation grid? Good point on the siphon, this is a mod thay can be knocked up easy enough. I just want to keep it as simple as possible for my first system.

That diagram helps a lot thanks for that.

Pipes will all be downsized, i was thinking they were too big but thought I'd better run it by you guys before spending anymore

It might be "better" to go larger, but the "best" size is the right size!


Although distribution of solids across the entire GB is "best" for mineralisation, unfortunately the piping of such a "grid" precludes a lot of area that can be used for plants, the piping may also get in the way during harvest etc. You can still achieve "good" results by running a ring of pipe around the perimeter of the GB as you'll rarely plant right against the sidewall of the GB and this leaves the middle of the GB free for plants.


The better the plan, the better the system...

Plan thrice, measure twice, cut once.

Bit of an update..

I have gone with 50mm SLO, and chose to run the 50mm right through to the CDM with the off takes to the two gb's being 25mm. Trying to find 50 x 90mm reducer was not happening, ended up paying a bit more for the pressure pipe but it all fits and i have the parts I need.

3000lph pump, still with the CHIFT PIST, constant flood is the go to start with the option of bell siphons further down the track.

Sorry but I don't have any pics atm as they would just be of raw materials but hang tight and I'll post it all here

Hi guys,

I am in the market for a backup air pump, I have looked on the fourm but am finding it hard to get the answer.

What is the right size backup air pump for a 1000ltr tank?

I found a cheapie that will do 240 Lph but I am thinking this may be too small?

Most of the AC/DC pumps I have found are small output..

Not keen on putting together a battery system myself, I definitely lack in the sparky department.

In theory, you should have about the same volume of air per hour going into the FT as the volume of water in the FT.

During normal operations when you've got water moving and pumps running etc, this is easily achieved; the problem comes when the power goes out. In "emergency" for short durations, less air can keep the fish alive until you sort out the problem (or the power company sorts out the power problem.) Many AC/DC air pumps widely used in AP systems deliver about 300lph which is sufficient air for a "properly" stocked system for a "short" duration.

http://backyardaquaponicsshop.com/shop/acdc-air-pump/

Awesome thanks Bunson

Hi guys, a little progress update.

Got two more IBCs, these will be the gb's x3 and sump and marked out the site, have cut the top off a third IBc for the FT.





2m x 12m, mrs Zeb wouldn't give me any more than 2m width but I will see how everything fits and maybe squeeze another .5 outta her

Got the 50mm for the SLO & CDM and the 25mm for the box irrigation and cut the gravel guards. Trying two different ones, see how they go.



Just need some uniseals and I can start cutting, pump is on it's way.

Found a 50mm threaded fitting for the standpipe, and a 50 x 40mm coupling





I'll update when it gets interesting

For the Gravel Guards - make the second one have bigger slits like your first one

Cut two of the beds up today, still got a long way to go but I have made a start

Hi guys,

Thought it was time for another update.

I cleared the site and installed border edging and laid the pea gravel, hopefully we can make a start on the actual install this weekend.

The original IBC tanks that I got had a glue in them, this was nearly impossible to remove, so a bit of time, energy and money wasted there.

I got a mate to hook me up with two cleaned IBC's and got the ST & GBs cut yesterday.

Cleaned & painted the FT too which the kids loved

Just a quick one re CF, how far below the gravel line should I flood to?

that wont be a quick one.... suspect variety of opinions.

assume from previous posts - using expanded clay, CF + Siphon.

expanded clay needs a bit of cover so it is stable and does not float off.
Then it comes down to your GB, CF + siphon - you may find your siphon actually allows WL bit higher before it kicks off.

my opinion is between 5cm and 10cm below top gravel.
my preference is to stay deeper, but you may have to help seeds/seedlings a bit when first put in.

for clay with a CF it will actually be wet/damp above the water line a little as well.

dont want too shallow in Perth as you will potentially lose to evaporation if surface is damp/wet.

[quote]The better the plan, the better the system...

Plan thrice, measure twice, cut once.