Alex's System

[almiper]

Well guys, i think i found the basic components for my system.
and i wan't you guys to pick it appart for me.

i have 6 grow beds, about 6 1/2 feet long, 2 feet wide & 1 foot deep (about 100 gallons ea)

about to purchase a fish tank (agricultural water trought) 2 feet deep x 8 foot diameter (750 gallon)

grow bed volume 600 gal total, fish tank 750 gal total. seems to me as if the ideal ratio would be 2 times volume of growbeds to fishtank is this going to be a problem? my idea is to have a much larger tank where i can add growbeds as time goes on.

what size pump should be used on this system...

is 2' depth to shallow for raising tilapia?

i'm in south florida temperatures are pretty similar to the ones in brisbane, or a bit warmer in the summer.

Thanks in advance.

Alex

[GaryD]

Hi,

I'll the skip the opportunity to pick your system apart but I'd be happy to help you get it going.

Let's start out with some questions....

What material is your fish tank and grow beds made from?
How do you plan to lay out your growbeds? Will they be located below the top of the fish tank or do you intend to gravity feed from your grow beds back into the fish tank?
What media do you plan to use in your grow beds.....or are you going to use floating rafts for your plants?My only observation about your proposed tank is that, at 2' (about 610mm) it's borderline in terms of its depth....bearing in mind that the water level will be a few inches below the top

It will do but your fish may periodically jump out of the tank. Covering the tank (or most of it) will help to keep your fish in and predators (and kids) out of the tank. It will also assist you to maintain optimum water temperatures in Winter.


Regards....Gary

[Murray]

Hi Alimpea,
Have you got any pix of the grow beds ? I would like to see the grow beds if possible. Very interested in all the different grow beds that are possible. A lot of folk here start off with old bath tubs as grow beds. See Beeso's post and his red bath tub. Bath tubs are a great way to go for an inexpensive start.
Muzza.

[almiper]

Well here we go with the details to my system.
Grow beds are fiberglass (they are actually caskets... long history there... i can get them for free.. and yes they are not used! :D)

the fishtank is a water trought used in agriculture looks like a heavy duty kiddie pool.

as far as the grow beds (caskets) go the will be above the fish tank. which i think will be inground at least by a foot. a pump constantly running to with a T so it can constantly shower over the fishtank for oxigenation and to fill the grow beds. and i may use some rafts for lettuce since the tank is so large.

i'm concerned about the depth of the tank but so far is the most reasonable tank i have found. A screen or such over the tank is a must due to the fact tha is so shallow.

Thanks again

Alex.

P.S. has anyone considered using UV filters in their water as an additional method of purification?

[almiper]

Sorry i forgot to mention... i think i will use pea gravel for media.

Thanks again.

Alex

[njh]

I'm not sure what advantage UV sterilization would have - we want the bacteria!

[almiper]

UV wouldn't kill the bacteria attached to the growbeds, but any viruses or bacteria floating free in the tank. your bacteria colony wouldn't be affected sisnce is not floating...

[Murray]

I have run UV light sterilisation as part of my Bio-filter. The manufacturer of the Bio-filter assures me that the UV light will not destroy the Bacteria. (bit hard to believe)
What the UV light will do is remove Iron from your aquaponics system and seriously deplete Boron and Manganese. The evidence for this is compelling. Tomato plants in particular suffer badly.
Muzza

[Macca]

So would you recomend against it then Murray?

[GaryD]

Hi Alex,

If you are looking for other fish tank options, have you considered the Rubbermaid range of products? We can't get them in Australia, but US friends seem to be able to access quite large containers at a reasonable price.

The use of caskets is novel and they will certainly be durable if made of fibreglass

Having the grow beds above the tank will allow you to use a single pump and to gravity feed back to the tank.

From what you've described, the irrigation system for your grow beds sounds like it might be continuous flow.

If so, I'd recommend a flood and drain arrangement instead. You can run it off a simple electric timer with a 15 minute on/45 minutes off pumping regime. Continuous flow irrigation of gravel beds tends to encourage channelling where Flood and Drain will give more even watering, better distribution of fish solids and good aeration.

Gary

[almiper]

Hi Alex,

If you are looking for other fish tank options, have you considered the Rubbermaid range of products? We can't get them in Australia, but US friends seem to be able to access quite large containers at a reasonable price.

The use of caskets is novel and they will certainly be durable if made of fibreglass

Having the grow beds above the tank will allow you to use a single pump and to gravity feed back to the tank.

From what you've described, the irrigation system for your grow beds sounds like it might be continuous flow.

If so, I'd recommend a flood and drain arrangement instead. You can run it off a simple electric timer with a 15 minute on/45 minutes off pumping regime. Continuous flow irrigation of gravel beds tends to encourage channelling where Flood and Drain will give more even watering, better distribution of fish solids and good aeration.

Gary

What i was thinking was to use a simple solenoid valve on a timer on a T... the water would be diverted to the tanks until they're filled, then solenoid closes the valve and the water will return to the tank that way is always aerated. i'm in south florida and temps can get pretty hot here in the summer. I am afraid the DO won't be enough otherwise

As far as rubbermaid goes the biggest tank i found so far is 150 gal. and is about $160 still, 2 feet deep
the round tank i found is $280 for 750 gal. and if the system works as i understand, i believe i'll be able to use about 15 grow beds.

Now i'm trying to figure out if i can power the pump "Off The Grid" some solar and some wind driven generators... still thinking about this whole setup.

Alex

[gardengirl]

Alex,
Y'all can find Rubbermaid stock tanks that are 300 gallons. The feedstore kin special order them if ya need. And it don't matter if the horses kick them, either. They're right sturdy.

[njh]

What i was thinking was to use a simple solenoid valve on a timer on a T...

Normal irrigation solenoids require significant (say 15m - 150kPa) pressure to open. You won't get a useful amount of water through with the sorts of pressures used in AP. They also often have integral meshes on the inlets, which will scum over with bacteria.

Gate, ball and butterfly valves all will work, but you'll need to work out how to turn them under timer control. (I would use a cordless drill controlled from an electronic circuit, see what you can come up with)

You could also build a diverter system using PVC pipe if you are mechanically skilled.

[Murray]

Yes Macca, I would not go with the UV light. I used it to get rid of the bad algae problem I had at the time. That is the main reason I installed the bio-filter with UV light. It was just amazing how it cleaned up the water and the algae.
It worked extremely well.
I was so impressed that I decided to leave the bio-filter in the system.

It was not until 3 or 4 weeks later that I noticed the leaves on my tomatoes becoming very light in colour and with prominent dark coloured veins. The fruit I was picking at the time ripened with patchy colour. A bit strange.
I had the Science Master from a Brisbane Northside school visit to look at my system and he told me what it might be. (mineral deficiency)
I got GaryD to come and take a look and he confirmed the deficiency of Iron, Boron and manganese due to the use of a UV light in the water circulation. Evidently GaryD has seen this problem recoded before by hydroponics people in their writings.
I was puzzled as to why my system should be mineral deficient as I am in the habit of applying mineral rock fertilizer and initially not believing the theory of mineral deficiency.
The UV light proved to be the missing piece in the jigsaw puzzle.
On switching the UV light off and adding some mineral rock, the tomato plants recovered over about 4 weeks.
Muzza