Backyard Aquaponics
A place to discuss aquaponics

OK, finally got a half decent grow bed above my inground 1000Lt tank.

I used a 60Lt plastic tub from "B".
I was going to drill 6mm (1/4 inch for the americans ) holes though the bottom, but due to laziness i used an angle grinder with a grinding disk to cut 10CM slots in the bottom about 10 of them in total.

I've found that the slots drain better, clog less and most importantly take less time

I then used a length of 15mm pvc pipe, capped one end and drilled about 42 4mm holes along the right, left and bottom.

I drilled a 19mm hole in the side of the tub and connected my "spray bar" with a threaded male and female pvc fitting.

I used the blue pvc cement (yuk) for the end cap and fitting.

Now a little trick, don't bother buying pvc unions, just mildly heat the end of the pvc and you'll be able to expand the end of it with another piece of pvc pipe, keep turning it as it cools and presto you have a home made union. I actually did this to couple a 16mm barbed poly fitting to the end of the pvc fitting so i could connect the pump which has 16mm poly tube connected to it, no cement or anything

The tub has been filled with expanded clay balls which have been part of a makeshift system for the past month.

The tub is sitting ontop of two pieces of angle iron for the moment until i figure out something better (maybe a piece of pvc tube sliced along its length?)

The submersible pump pumps water from the bottom of the tank to the spray bar which very evenly distributes water over the clay balls. The water then falls back to the tank from the slots in the bottom of the tub making a very pleasant trickle noise and airating the water for me.
The pump will be left on 24/7

The greenhouse "dome" i mentioned covers the whole thing until we build a you-bueat green house

I've tested all the water parameters (i cant help it! ) to get a base line.

24/06/2006
7:30pm
ammonia=0
nitrite=0
nitrate=0
PH=8.0
Temp: 10

This figures confused me for a while, as i was either expecting high ammonia and nitrite (the may be a decaing fish and plant matter down the bottom ) OR measureable nitrates if the system is cycled.

The only thing i can think of is that the bacteria has cycled (zero ammonia/nitrites and the algae (lots of it) has/is consuming the nitrate.

Anyway, i popped out and bought 5 goldies and will now liberate them into my tank

I'm going to heat the water to about 15C tonight and then turn off the heaters and see how my heat losses go (i know i have a temperature logger stashed somewhere in this mess )

The tank is in the shade (i was thinking about summer) but the green house i'm designing will be getting full winter sun along its side and during summer the sun will track almost directly above it so i'll just place a line of shade cloth along the center roof when the time comes.

Will keep you all informed

Steve

looks great steve...I like the look of the clay balls..nice steady stream of water flowing out of your sprayer..what type of pump did you end up using?

You going to use the galv tubes bent to a hoop for your you-beaut-greenhouse?

LB

Thanks LB, you inspired me

Yeh, i was ultra impressed with the water coverage, had previously tried it the way you have with the poly pipe and a small pump, as wasn't too impressed.

Pump is: Damn, cant find the box! will get back to you.

Its about 30 Watts submersible, will get the flow rate and brand for you.

Nah, going to make up a rock solid nice looking one from square pipe, weld it all and line it with plastic. Dads got one at his house, and i've asked him time and time again to give it to me. General answer is NO!

Just some questions to get all that info out of your head!!!
How many Jades you going to put the tub?
What you going to use for aeration?
How many heaters are you using to get the temp up?..(I think the earth would hold a lot of the heat in..good move burying your tank)

Regarding your Dad's greenhouse, why dont you send him out for dinner one night and I'll come pick you up with my trailer attached!! LOL

steve,

do you know the displacement of the clay balls? I'm looking for a medium that will only take 20% water to fill in a flood and drain.

Monya

System looks good - wish we could get those balls here in Cairns - I have had no luck getting them here as of yet...

AM, Surely your have people that grow.........um tomatoes.......in cairns?

Seriously, just pop into any hydroponics shop, they'll have them alright
Thy're not cheap though. Can't remember the price, but not cheap EB might remember the price

Monya, Will work out displacement for you in the morning Hang on, it is morning

LB, Will be putting them in slowly, probably 10 to start with, then look at my levels and make a judgement call. Could probably put all 40 in at the size they are at, but might be a prob when they grow. Will have to review joels book and previous posts on the matter. I'm hoping to get away with the airation provided by the water draining back into the tank for the mean time. Damn i'd love a Dissolved oxygen meter.....$600. Anyne from melboure got one and wants to be my friend

I have put 3X 300W heaters in for the moment, and am just about to go out and check the temp. will check it again in the morning. If it comes up to temp i should be able to drop at least one if not two heaters out of the system. Once its up to temp the only heat energy in need to input is whats being lost to the surroundings, which i hope is not huge due to the mini green house and the tank being buried.

Have thought about taxing the greenhouse

hey steve, it all sounds great. Greenhouse wouldn't take long to pay for itself if a couple of heaters could be dropped out of the system

Hey, nice one Steve...

I'll be inbterested to see how you go with the water splashing over the surface of the rocks like that, you may end up with an algae problem growing on the gravel surface, only time will tell.. Did you cut much off the top of the tank?

AM, the expanded clay like Steve used is available from any shop that sells hydroponic equipment, including the 'B' shop. bloody expensive though, about $1 per litre..

Hi,

For those of you who may be contemplating using Light Expanded Clay Aggregate (LECA) for other than continuous flow grow beds, the cost won't be your only consideration.

The little clay balls float so if you're going to flood your beds......and then drain them......you'd be better of using the gravel.....and you won't have to mortgage your house.

The little clay balls are excellent for a trickling bio-filter like Steve's using over his palletainer tank. They provide lots of surface area for the bacteria to grow and the air spaces between the balls allows for the water to take up oxygen which is essential for the fish and the bacteria.

They'e also light enough that you can move them without getting a hernia.

Gary

Very true about the weight gary. One person can move a 120 Lt bag, try and do that with gravel

I've played around with them for a while as a bio filter medium, and what i've found is that if you soak them in water for long enough then a high percentage of them will absorb enough water to sink. I have quiet a few of them sitting at the bottom of my aquarium:) worth a play around with.

Ok,

Checked temp at mid day, 15.5 in the first 30 cms and 16.5 in the last 30cm depth. Which puzzeled me, until i realised that the top 30cms doesn't have any dirt around it, might "mound" up some. I think the dirt is providing excellent insulation.

will leave it another 24 hours see if i can squeeze 20C out of it, and then drop out a heater.

Monya, took some measurements for you;

A 1.6LT container that took about 0.6lt of water once filled with clay balls.

By my calcs you need 37.5% water in a given volume filled with clay balls,

ie: 100 litre clayball grow bed will take 37.5lt to flood

hope this helps.

Steve

Most of the discussion around the displacement rate for grow-bed medium has been centred on having a higher rate (ie less water needed to fill) so that not as much water is lost from the fish tank in a flood and drain system.

Of course if the displacement rate was too high then this would also indicate that there is not much air space for the roots to grow.

It would be interesting to know what the optimum displacement rate is considerred to be for this type of use. That would then assist in choosing between diferent gravels (or other medium).

Thanks steve,

that's about the same as the gravel I tried. Maybe that's about standard.

Good point VB,

maybe EB knows what the optimal displacement is??

monya,

Displace ment will be exactly the same for media of a given particle size, the only thig that will differ is the weight per volume due to themediums density