Backyard Aquaponics
A place to discuss aquaponics

If you don't want to go higher..

Can you drop the grow-bed down a notch, and then add timber under the grow-bed.. Bring them back to the original height..

That way you don't have to worry about the chance of any sag..

Juergen

it looks like you could turn your grow beds 90 degrees and still have the same or perhaps even less unsupported overhang or add timber and it wouldn't matter. A 90 degree turn would take up less of your pond, or allow another grow bed in the same space.

And I think I mentioned $12.5 a bag of scoria.

I didn't mention at the time that it's cheaper by the trailer load.

and this post on volume per ton of media might be useful when you are trying to compare cost

Planning for future expansion for more shelves for grow trays even before completing the first system.

No internet again yesterday since morning. Internet was on in the evening.
No internet again this morning. On again in afternoon.
Very frustrating. BTW, it is Adam Internet.

I have been searching for pebbles in Adelaide so that I mix pebbles with clay stones, the lower one third pebbles (for worms) and the upper two third clay balls in preparation for setting up grow beds.

The nearest supplier in Campbelltown was Newton Sand and Metal.
Did not have scoria which seems attractive because of relative light weight.
Got samples of blue stones and river grabble. Was told that blue stones had high salt content.

I put the samples in jars with pond water for one day.

Today, I got the water test kit from a local aquarium store. $59.95, $10 more expensive that Sydney and Perth price I see on internet.
Tested four samples of water:
1] tap water (left),
2] pond water (right),
3] pond water with blue metal,
4] pond water with river gravel.

Result was somewhat surprising.


1] tap water ph 7.2,
2] pond water ph 7.6,
3] pond water with blue metal ph 7.4,
4] pond water with river pebble ph 7.2 (?).

Why is ph lower with stones? Did not expect this. River gravel gave much lower ph than pond water.

I looked for another supplier further away (Pooraka Landscape Supplies) which had scorcia. Price was $93/cubic yard (why yard?) or $155/ton. And $50 for delivery.

Local supplier (Newton) price for blue metal: $54/cubic meter, $60 for river stones, both 13 mm. Delivery $25.

Well, the choicee seems obvious: 1cubic meter of River stones from Newton to be delivered.

Sejin

Yes, I can lower the top shelve on notch down.
But then, lower shelve will get less light.
Mine is three level operation if possible.
On water level, there is floating raft.

This is just an experiment to find out the effect of three level grow surfaces, but subject to change when the results are available.

Sejin

Got some plumbing parts for channeling pond water beyond the original commercial bio-filter.
Reducing 40 mm to 25 mm.
From pump under pond water.
Left outlet (40mm) to filter, right (25 mm) to two grow beds above pond.
Toward top (25 mm), for distributing water to other parts of garden.

$70 for these parts. Not bad.
Poli tube and parts will be used for each local parts.

Sejin

The dissolved carbon dioxide in the water acts as a mild acid. This gives short time false readings (Thanks for my education TC)

If you leave the water for a day or two, then retest with the de-gassed water, you will get very different results.

Try the tests with your rainwater.

And also try the pond water with the high range pH test chemical. When it shows maximum like that, it may well be higher. Even at pH 8.2, the low range test bottle shows pH 7.6.

My 2 day old Adelaide water shows pH8.2 at the moment, and I'm starting to see white salt deposits around my pipework in the system.

Another test to try with the gravel is to add some vinegar. if the pH is to high, I'm told it will fizz, but the only real test is to start with a lower pH water and see if the gravel raises it. All those tests will show 8.2 if you let the water sit for a few days before testing it.

me think you might just hate me..

I'm not sure what you paid for those valve's.. But I get mine for a bit cheaper..
3/4 valves[20mm] about $3.00
25mm for about $4.00

I try not to use B's as they are way to expensive..

Juergen

Ah, nope... if the gravel contains a carbonate compound... like limestone...

Then the acidic pH of the vinegar... will dissolve it... make it fizz....

cool thanks

I thought all the high pH rocks were carbonate packed

Either way. Rocks + vinegar = fizz ....probably bad

But I'd do the tests again using old water or water with a lower pH and see what results you get. Adelaide water is doing all kinds of crazy stuff at the moment.

Distilled water should be pH neutral so is probably a good alternative to tap water to test the media.

Hi BW and Rupert,

The first thing I did was to take a jar of viengar and test the stones in the store.
The stones did not fizz.
So, I took samples home, and put them in jars with fish pond water.
Waited one day, meanwhile buying the water test kit, and then tested water.

A suprising result was that stones lowered ph of pond water.
Still do not have an answer for this. Does anyone?

After making some enquiries on alternative stores and choices, I decided to order half tone of the 14 mm river stone gravel from the first store (Newton) because it was cheaper delivery and gravel from this store lowered the ph of pond water.

I did ordering by phone, and there was some confusion, and 30 mm stones (some stones were as large as 60-70mm) were delivered. I had to ask the delivery person to take them back and bring a crushed 14mm gravel. Totally unnecessary work was created by a confusion on terminiology of gravel.

0.5 ton $30 (inc tax) and $25 for delivery, with no extra charge for the confusion.

I had the gravel poured on my sloped driveway partly because there was no other choice and partly because it might be a good place to wash the gravel.

After some washing by hose and overnight shower did some additional work.
I intend to put gravel in a big container filled with water, and take out from there before transferring to grow bed.

In the picture, it looks like there is more than the real quantity, 1.5 ton and roughly 1 m3.

Hi Jurgen,

I read about not buying from Bunnings. I place I bought gravel from (Newtons) was a construction and landscape supplier, and they also had irrigation supplies.
Because I read about advantage of buying from an irrigation supplier, I bought from this place without actually comparing prices with Bunnings or Mitre 10.
I cannot find where I put the receipt, but 25mm ball valve was $7.

But your price for the same part ($4) is much cheaper. Where did buy plumbing parts?
I will need to buy more as work progresses.

Sejin