Backyard Aquaponics
A place to discuss aquaponics

For a while I have been wondering what use is this sand we have all over the place in Perth.
It's water resistant and difficult to grow what you want without constantly adding supplements like clay, soil wetter, fertilizer, worm juice, compost, food scraps, manure, etc...

I have been reading up on iAVs or sandponics recently. I wondered, can this sand we have everywhere be used in an iAV system?

Here is my attempt to see if this works.

Here is a typical pile of dirt.


I have two filters set up. One is an old colander to filter out the large objects.
The second is a stretched stocking which filters out the small debris.



Looking down into the large filter.



This is the sand left after the large objects have been filtered out.


As you can see here, even though the bucket has been flooded, the sand underneath is still dry.

Here is some more of my sand cleaning pics.

This is the stocking filter to remove the small debris from the sand.



These are the very small particles removed from the sand.


This is the now filtered sand, after having removed the large objects and the small debris.

Here is a sample of sand I cleaned earlier.


Here is a close up of the sand. You can see how varied it is.


Here is the TDS reading for water from the garden hose.


Here is the TDS reading after the water was added to the sand. Even though the water is cloudy it still didn't show a large increase.

I think if I were to diy my sand, I'd use a large piece of window screen. More than likely loose the sand on the smaller end of the prescribed size range, but the silt should be gone.

That is good looking sand in my opinion. I suggest doing the sand tests for iavs to verify. But what a lot of work to get the clean sand. That would be a big operation to get useable amounts. I have over 3000l of media in my system, there is no way I would want to mine it myself. I am hopeful I never need to clean it.

Thank you for the thoughts.

At the moment I am waiting for the sand to dry out to see if it will still be water resistant.

Cleaning the sand is a slow process but I am only going to do a small test and if it works I will think of an easier and faster way to clean it.

I am using an old laundry sink (stainless steel) and only part way filling it. I covered the drain with some fly screen and the sand is staying in the sink.

At least I know all the water drains out.

I can get Gin Gin Sands (silica) here and it costs about $80/trailer I think. That will be option 2.

I have tested the washed sand and it is still water repellent.

Looks like I am going to start option 2.

What is "water repellant" sand? Is it coated/contaminated with something?

It is hydrophobic sand. I tried to find a video of it but couldn't find one.

I will take a video as it's much easier to see what I mean than to describe it.

Here's a quote about Perth sand from a Perth gardening website:
"Sandy soil like we have in Perth, is often water repellent or non-wetting. In fact, Perth has some of the most hydrophobic soils in the world."

Well I recently found out I can get 30L bags of this Gin Gin Quartz for $6.

So I have one of them now and I am going to try a small test.

I saw on one of the IAVs sites not to use the sand as a filter without plants. So I will need to plant something as well I guess.

I also need to get the SLO I made set up and hope it works.

I picked up some yabbies last week so that's all I have at the moment.

On Saturday I washed the Gin Gin Quartz (sand). It had a lot of fine silt or grit in it. I washed most of it out using a stocking as a filter.

I set up the sand in an old laundry sink and made the furrows etc...

Before any of that I wanted to get my SLO setup done, based on dstjohn99's post about IBCs and SLOs, I used 25mm pipe.

To do that I then had to fill up the tank with yabbies with another 600L of water... so I set about to do that over the following days.

Finally get it filled, the tank is now cloudy with gunk in the water being cycled by the pump, baby yabbies are swimming around and I fear they will be sucked up into the SLO or the pump.

Anyway I get the cycle started and the sand bed worked beautifully. The water followed the furrows, or rather filled up to the level of the furrows and slowly trickled out. It was too slow for the pump and it quickly ran out of water to pump.

Changed the whole setup to just use a filter but I didn't have the right fittings and so went back to the pump in the tank cycle again just to keep it oxygenated.

Not ideal but at this point I trying to find the time to do this right.