Backyard Aquaponics
A place to discuss aquaponics

Got a bit done today, but then had to go out to lunch. Who organises lunch on a Sunday?

Still blowing a gale, so couldn't put up the fabric.

Put the first of the sumps - old baths, wastes connected to form one volume - in position. The growbeds just drop directly into the bath underneath.


They sit very nicely within the line of the structure, and also form - by way of beams, not yet in position, placed across them - the under support for the growbeds. I do like an item to earn its keep.


Kathy filled in the trench. That's why she looks grumpy.

Did some more work today...

Set up the waste connections between the two bathtub sumps, making them one volume:



Won the sump pump, so tomorrow I shall set up the return line:

Also started work on the water feed to the growbeds.

I shall be using a SLO fabricated from 90mm stormwater pipe, which feeds into a full ring manifold running horizontally around the fishtank. At each growbed location, water is taken off the manifold.

This will be done by way of a downwards-facing T, capped, with 25mm M thread-32mm PVC adaptor inserted in the cap. Here's the parts:


Here's the unit assembled (this side will be inside the manifold):


Here's the other (outside) side:

And here's the complete water take-off:


(It will face downward when in place).

Tomorrow's tasks:

• fabricate the standpipe drain for the first growbed
• test the sump for water-fastness
• test the sump pump
• fabricate the sump water return line
• maybe get a start on the SLO and manifold

After a couple of days off to chainsaw up a tree that fell on my roof in the high winds, back into it today.

First, the SLO drain was installed (it's shown attached to the water distribution manifold):


Here it is inside:


Note the hole I drilled very very carefully very very 90-odd mm too low. More fibreglassing...

Also please recognise I am using reclaimed parts as much as possible - I didn't glue that T on the 90mm stormwater on that jaunty angle; someone else did.

From there, I moved on to assembling the water distribution manifold:


This runs in a full ring around the fishtank, dropping into a growbed on each side.

Looking pretty cool so far. Hope you are going to give those components a wash to give it some bling

Then the kids came home:


From there I moved on to plumbing the sump pump:


I'm not bothering with a non-return valve, as the lift is so low.

Here it is inside:


The capped T is for air injection; that's a tomorrow project.

Turned it on, and everything worked!

The sump pump cut on just as the sumps were about to overflow; nothing leaked; Kathy brought beer. Life gets no better.

Ah, yeah, um... it all looks pretty bloody grotty, doesn't it (even the kids)?

Was only joking mate. The system looks to be coming together really well and its good to see a plan coming together

I wasn't! It does look grotty!

At least the kids have had a bath tonight...

Got some more work done yesterday.

Picked up a load of crushed brick and set the boys to work with a pressure washer. The boys got quite wet; the crushed brick didn't get very clean.

Decided to rework the sump pump plumbing so it went through, rather than over the lip of, the tank. This will allow me to cover the fishtank more neatly:


I also finished the air bleed. One piece of 20mm electrical conduit with a V cutout. Here's the cutout:


A 20mm holesaw into the cap on the T in this photo (you can just see the top of the 20mm conduit), and a bit of silicon to seal it in position - V cutout facing downstream:


Works a treat - lots of bubbles.

(I also fibreglassed up the, ahem, extra hole in the fishtank you can see under the SLO drain exit.)

I may have to rework the end of the sump pump plumbing. I want the water to swirl around the tank; at the moment it bounces out of the corner and creates two vortexes in opposite direction. I tried cutting the length down to what you can see, but only a slight improvement.

I may extend it around the corner, or even down into the very bottom and around the corner.

Still more progress.

Kathy washed wheelbarrowfuls of crushed brick:


Apparently she didn't want me to take these photos:


I can't imagine why:

And here's the result:


However, not all is well.

I extended the pump line down to the very bottom of the fishtank, in order to promote swirl and inject air bubbles as deep as possible.

Sadly, I got a fountain:


The extra back pressure forced water out of the air bleed; no bubbles.

So I tried putting the air bleed T right at the end of the pump line, and using a very long piece of conduit to draw air from above the water surface, but no bubbles were injected.

The other problem that surfaced is the the fishtank is siphoning back through the pump; I can put an anti-return (foot) valve on it, so that's an easy fix.

But how do I solve my no air bubbles problem?

the air intake (for want of a better word) might be too big.. i use 6mm tubing and you can use more than just 1 tube.. this gives a good spray of bubbles into the tank...

your pump appears lower than your fishtank..so there will be some siphoning as water runs back down to the level of the pump when it is not working.. a non-return valve will work...and maybe try straightening the pipe into the fishtank. or use a t join at the top.. my 6mm tubing is enough to break the siphoning when the pump is turned off..

i think there was some concern in using electrical conduit due to lead(??) in the manufacturing of it.. could be worth a search..

great design.. and plenty of photos!!

good luck!!

Well in regards to your venturi (the bubbles generator), it works based on having a pressure differential across the restriction. So in short, your conduit you put into the T piece with a cap should cover a large portion of the hole as seen from the side. In turn with sufficient flow through this restriction, the velocity of water on the other end of the restriction creates a vacuum and sucks the air into the water path.

Well in extending your pipe further in the water, the water flow from the pump will now need to overcome the water head (water above the pipe outlet) to push the water out. And the reason water is coming out from the air intake is because you have lost your pressure differential across the restriction.

So to overcome this, provided you have sufficient flow diverted to this venturi pipe, shorten the depth into the water (ie don't go too deep)...

Secondly, for creating a swirl, what I found was that the best way to create a swirl effect (well for a round tank anyways), is to have water coming out of an elbow at 90degC to the water surface... and have it as close to the top surface as possible... The pump uses a lot of less of its pressure to push water out at the top surface compared to the water too far below the surface. I found that using a 45degC elbow, similar to what you have, does not create a good swirl as it loses pressure pushing water into the water depths rather than pushing water in a circular fashion.

Although in a rectangular tank, you may require a different method.

Suggestion though, as venturi piping do not have a lot of pressure generated, you do not need to glue the pipe until you found a configuration that suits you. So don't use glue and test a few setups...

I think I did add a photo into my First System thread of the new venturi setup I made. See below...