View Full Version : Alternatives to Lightweight Expanded Clay Aggregates (LECA)
gareth_j_jones
03-22-2011, 04:55 AM
Good day all,
I am in the process of setting up a fairly sizable system (1500 liter tanks and five 375 liter grow beds). Ideally I would like to use Expanded Clay as a media but the costs are prohibitive down here in South Africa. Can anyone suggest an alternative? My understanding from all I have read is that crushed stone media - besides being heavy, can cause PH problems.
Thanks
Gareth
keith_r
03-22-2011, 05:33 AM
look for "river gravel", prefereable size (for me so far) would be something like a mix of 3/8" to max of 3/4"
use some vinegar to test the media, if it bubbles you don't want to use it..
scoria is good (lava rock) but hard on the hands..
pea gravel looks too small to me, and might be easier to clog
i used 1/2 river gravel and topped off with hydroton (expanded clay)
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gareth_j_jones
03-23-2011, 12:52 AM
Thanks Keith_r, will do JCO.
rfeiller
03-23-2011, 08:24 PM
welcome to the forum
aquaarche
03-23-2011, 08:43 PM
Just pay some young men to sift you out some pea gravel from a local river or stream. it will cost you less than importing fired clay medium.
there are a few guys who make pottery here that I wanted to get to make small clay balls and fire them but that cost was prohibited because of their greed. for a 10lb sack they wanted $12. Remember here they get the clay and the wood to fire their homemade kiln for free. Even the kiln they made from free materials.
anyway the water beds with floating puzzle mats have proven to be better than gravel. but depending upon what you want to grow just adjust the size of your pot you place in the float bed. for tomatoes and squash and beans use larger pots with gravel in them. for lettuce use net pots. but a water system takes two months to get the bacteria to level. river gravel will already have bacteria in it naturally. so river gravel in your pots will give you a bit of a jump to producing Nitrober and Nitro bacteria needed to convert Ammonia to Nitrite, and Nitrite to Nitrate.
urbanfarmer
05-11-2011, 08:59 PM
Got a guy using http://www.bigriverind.com/pages/produc ... heet11.pdf (http://www.bigriverind.com/pages/products/TechSheets/GRAVELITETechInfoSheet11.pdf)
I think it was $70 by the yard. He picked it up in his pickup truck, standard 6 foot bed piled high with tarp tied down. I been thinking about it, but... You can get maybe 2 bags of LECA for that... you get 8x more of this stuff!
I think most concrete type places sell this. Stucco should start buying it and selling it in 50 Liter bags. Call it Stuccoton or Stuccolite or Hydrolite... idk, but it should sell like hotcakes!!!
IF you have some nice course sand somewhere, you can try that. I have always wanted to use course sand to try to rig up a good setup. Completely experimental though, and a lot of proper design would have to go into place. A swirl filter on the EXIT along with some other filters would probably be MANDATORY, but if you use physics right, it should be possible...
rfeiller
05-11-2011, 09:24 PM
i don't believe it is available here in CA. i haven't seen it on any of the design mixes that have come across my desk, including liteweight. i will check on it though, good info
urbanfarmer
05-11-2011, 11:51 PM
My only question is if it was "safe" for use. I don't know what all is in the dust you wash off, but I assume more of the same aggregate just crushed up, in which case it's fine.
If you find anything cheaper let me know!
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