Backyard Aquaponics
A place to discuss aquaponics

Hi guys,
I noticed an absence of 'best practices' for cleaning gravel on this forum.
So I thought I'd ask the question.
Fancy gadgets, trommels, washing machines are all well and good, but the simpler solutions are what I'm after here.

I have posted this on my system thread but here it is again :-)

Well people, the gravel has arrived
[web]http://www.backyardaquaponics.com/forum/album_pic.php?pic_id=336[/web]
and the cleaning begun[web]http://www.backyardaquaponics.com/forum/album_pic.php?pic_id=337[/web]
hmmm this is hard work.
So diligently I searched on the forum, yet found no description of how to wash gravel efficiently. So I thought I'd put up what I came up with.
First: Fill a barrow with water and place it next to your GB [web]http://www.backyardaquaponics.com/forum/album_pic.php?pic_id=338[/web]
Get a bucket (or other transport medium) full of gravel and dump it in your barrow.
[web]http://www.backyardaquaponics.com/forum/album_pic.php?pic_id=339[/web]
now you need to wash it. get a gravel rake from the garden shed and rake away until all the gravel is wet.[web]http://www.backyardaquaponics.com/forum/album_pic.php?pic_id=340[/web]
then simple rake it into your GB, leaving all the nasty fines behind.[web]http://www.backyardaquaponics.com/forum/album_pic.php?pic_id=341[/web]
And you're left with said nasty fines all through your barrow. This is a pic of how hard it is. To make that hole took about 8 hits of the shovel!!
[web]http://www.backyardaquaponics.com/forum/album_pic.php?pic_id=342[/web]
Even with the barrow almost vertical the fines are set like cement in the bottom. Imagine if you let this stuff get into your GBs your flow would go to nothing![web]http://www.backyardaquaponics.com/forum/album_pic.php?pic_id=343[/web]
I had to add a screen as a further mod to my GB (mentioned earlier in this thread and also in SNAG's new system thread) to keep the gravel from interfering with the float valve.[web]http://www.backyardaquaponics.com/forum/album_pic.php?pic_id=344[/web]
and finally we're done... I just hope I don't have to move it![web]http://www.backyardaquaponics.com/forum/album_pic.php?pic_id=345[/web]
And now I check my messages and see that my boss says I'm to be in Sydney on monday for 2 weeks! Whatever will come of my AP project in all that time... I still have to plumb my GB...

This image pretty much sums for my washing exp:


I.e. I used relatives to wash my gravel. His papery skin meant that his hands were bleeding by the end. There were lots of quips about "working him to the bone".

I only washed 1cu metre, so it was bearable.

was that you with the 1 m3 or your grandfather?

So that's a flyscreen from a window, and you sprayed water onto the gravel yes?
Pity we're in water restrictions, or I'd have done similar I think...
Thanks.

No wonder the media is so red...

My attempts so far...

Method 1 - Use an old wire sprung bed.
Pros:
1)Does a great job at cleaning fines and sand from gravel.

Cons:
1) Uses lots of water
2) Gravel gets stuck in wire spring, hard to shovel out.

Could be improved with some perforated sheet metal over wire and no water restrictions.

Method 2 - Laundry basket in cement mixer. (improvised trommel?)
Pros:
1) Use little water - A dry run with no water, separates a surprising amount of silt.
2) Water that is used can be easily captured in mixer bowl and re-cycled.

Cons:
1) Great at removing fines, but sand stays stuck to river pebbles.
2) Need to buy a new laundry basket !!

This could work very well with gravel that only contains fine silt.

Buy your gravel in winter, just after its rained hard and ask the bobcat driver to take the scoop from the top of the pile .

Ingenious Scott .

Nice...
I had access to a cement mixer, but wondered if it'd be worth it. Mainly cos I couldn't come up with the basket idea. And I though Dad'd kill me if I drilled holes in his mixer
Very impressed am I.

when i build my new system at my new house, i'm going to buy pea gravel and go in unwashed for 2 reasons.
1. we are trying to save water with aquaponics. even though there's a net gain with it i still think we waste massive amounts washing gravel.
2. no matter how much we wash it, it will STILL go cloudy.

My plan is to go in with my little $30 sacrificial pump and just do one big flood through the bed initially to fill my 500L tub. let this settle a bit then pump this on to my dirt garden for normal watering so it's not wasted, and dump the mud that's left.
I'll do a few cycles like that till i get the worst of it out.

Wheres the ute and fire hose thread

Timmy, I think most ppl re-use the water rather than keep using clean stuff, just makes for a better story with hoses flowing

Gravel washing is getting rid of the fines with exaggeration (see who can spin the biggest yarn)

sorry, we didn't take any pictures that day

Timmy, at least get the gravel really dry and sift it slightly to get rid of the clumps of mud and sand... I've had bits of gravel before that were actually dried mud. You really don't want it clogging all your pipes... get as much out as you can, doesn't have to be using water...