Backyard Aquaponics
A place to discuss aquaponics

My system is going to use red scoria/ lava rock. We have been washing 2 cat litter jugs of it for nearly 30 mins by adding water, churning with a shovel dumping the water, and occaisionally flipping it upside down but the gravel doesn't seem to be getting any clearer. How can you wash it efficiently?

Try this - fill a storage tub with water, get a colander, fill the colander, and swish/spin the colander to get the sand and dirt out of the gravel. Several water-filled tubs in sequence would help get the gravel completely clean by the end of the line. You can continue using the same water if you let the solids settle to the bottom of the tub after a couple hours. You can also use the water instead of wasting it, after the solids settle to the bottom.

the lava rock will likely continue to turn water red for a while, eventually you will have to just put it in the system. Stirring with a shovel is probably breaking the lava rock up more than it is cleaning it. The colander or water plant basket with gravel in it swished in containers of water works quite well. Make sure your containers of water are deep enough to make swishing easy without stirring the stuff on the bottom and if you have the containers up on something of a good working height, it is even ok on the back!

more elbow grease

froggy, scoria is horrible for the fines............just let it be after you've given it a bit of a wash. most of the fines will settle out after a week or so. you can then remove them if you want.

Thanks for the help. We're glad to hear that the red in the water is normal. We've found that the water runs clear after some washing as long as we don't stir it up with the shovel.

Take a 5 gallon bucket and drill a whole bunch of holes in the bottom. Then stick it in another bucket and fill half way with water. Throw your lava rock in and swirl it around really well with a gloved hand. Do it in small batches, the smaller the batches the cleaner it will get. Pull the bucket with the holes in it out and let the water drain into the bottom bucket. Give it a final rinse with clean water. Repeat 1000 times untill everything is all clean.

1000 times lol

Get someone else to do it

If I had the money down here I would just pay that willing hard working ethnic group from down south a few bucks an hour to do it for me

Unloading from a trailer we had one person with a shovel of clay/gravel and the other squirting with a hose before loading it into a wheelbarrow. Took 3 people 2 hours from memory. "We call that the "Induction".

Yep - except here, I am the foreigner.... I don't remember sorting and washing the gravel being that hard - but then again, I didn't do it!

The basket or bucket swish technique seems to work pretty well.
1-It is relatively water efficient as you arn't spraying away water the entire time.
2-So long as you set up your work space well, it is relatively easy on the body.
3-One person can do it alone if necessary.

With two of us working at it, We filled tow of my big beds (32 inches by 93 inches by 12 inches) over the course of two days though we could have done it in one had we started in the morning. One person washing while the other totes buckets and trade off every now and then to work different body parts.

This is a pic of my worm harvester / casting & egg capsule collector. I have used it for years as a compost sifter and gravel classifier as well. Different size screen can be installed for whatever size particle you want falling through it. So the drum rotates and the stuff falls through...pretty elementary.

I was considering a reservoir below with bilge pump to a spraybar above. Shovel in the gravels, drum rotates and angle is adjustable. Fines get washed out and gravels fall out on other end all clean. Water with fines fall through back to reservoir. Pump could be set up off bottom with a filter material over the suction.

Homemade version out to be simply made from a steel or blue plastic barrel by cutting sections out of it and fixing the size screen you want around it on the inside. Set it on some sort of roller and there ya go.

I think the harvester would be appropriate for dry sifting or winnowing of gravel to save water. Then if it still needs washing with water it might be worth running again but if water is used right away, that poor pump will likely get way too much grit in it's diet.