Backyard Aquaponics
A place to discuss aquaponics

I bought 20mm scoria and some seems too large to be honest.

i think you will be fine at 10mm, if you are worried about losing too much mass from washing tiny rocks away, then use your mozzie filters rather than a sieve, however anything the size of sand or bigger will be left behind.

10mm must mean anything that falls through a 10mm hole
I have some <10mm gravel in my first system GBs and it works fine- the guard that stops the media from going down the gurgler just has to have holes smaller than the smallest rocks- which is why Agi pipe with slits is good.

Yav yes I agree, saying washing is not required just seems silly- not only is there the large anerobic zone in the bottom of every GB risk, but it will also grind away your water pump.

This is going to be a very long, monotonous process. I just had a quick attempt at rinsing the scoria and it needs to be rinsed in fairly small quantities to get rid of the dust.

Is the scoria I have too fine/small???

*edited to say: Just saw your replies about scoria sizing Gunagulla & Yavimaya - PHEW! I just felt sick thinking I had all this scoria I couldn't use..

it shouldnt be too long chick, maybe save the work for a warmer day if need be, i found i got pretty wet doing it the way i said.

it took me about 1 day to do 3m worth of scoria, but some was already in the bed i used to wash the rest and boifilter was 1 step away, make things as easy for yourself as you can.

This is what my media guards look like. Do you think I should cable tie a sleeve of aluminum insect mesh to the outside of the guards to stop the finer stones getting through?

if those holes are 6mm or so, then no problems what so ever.

if they are 8-10mm, you may get some of those more odd shaped rocks sticking into the holes, etc.

but in essence, once the bed is full and alll the rocks are locking each other together, you wont get any rocks squeezing thier way into a hole unless its positioned perfectly to do so.

Ok just checked the weather forecast and there's rain predicted for tomorrow - should I cover the gravel with a tarp to prevent my precious scoria washing away or should I let the rain rinse it for me?

leave it, none will wash away unless you get a proper flood that would also wash away your pot plants.

the rain wont clean it one iota, well it may clean the very top layer if you get a lot of rain, have fun scooping that off though.

I had a vast pile of river gravel out in the rain for quite a few heavy falls- and it made no noticeable difference to the fines, it just isn't heavy enough- no comparson to a jet from a hose.

Well. First of all it rained last night as forecasted and my gravel didn't wash away...

Secondly: Yavimaya, I'm sorry I doubted you! The bucket rinsing trick does in fact work and get rid of most of the silt.

This is the scrapings from the bottom of the wheelbarrow (lots of silt/dust) before rinsing:



This is after rinsing. (Which involved dunking the seive in the bucket 5 times)



I decided I would change over the bucket water after 2 wheelbarrow loads. This is the sediment that was in the bottom!



Now my scoria is still not 100% dust free when it goes into the growbed as you can see in this photo it still turns the water red.


But I'm still happy with removing as much dust/silt as I have.

Aaah the dreaded gravel washing. An essential step to becoming a Aquaponicist.

lol thanks SC.

so many times per day everyone around me doubts my every word, so many times per day they are all proven wrong.

hehehehe.

I find that doubtful yavi..

the part were people doubt me??

crazy isnt it!

Well. I did it. All on my own. 5 wheelbarrows of scoria and GB#1 is full! Woohoo!