Scoria - Columbia River Lava Flow - basalt in origin...Okay for media beds?

[Converse]

  I just found a local source for Scoria.  It is a red lava rock that is local (Columbia River Flood Basalts).  I did a fizz test on it, and it did not produce any fizz....So I plan on using this for a new media bed I am adding...but before I go ahead with this, has anyone had experience with this rock...and was it okay? Should I have done any other testing?  No pH challenges down the road for anyone having used this?

 

- Converse

[Eric Warwick]

I use "red lava rock"  for my hydro' systems, and they're inert. People in Australia use it with no problem, and it is essentially the same give or take many local conditions. A guy at the Mother Earth News Fair suggested it (purple rain aquaponics), so I think you should be able to use it. Good luck! 

[Sahib Punjabi]

Hello Converse,

Given you have already done your "fizz" test and did not find any fizz, I would say go ahead and use this rock. I also use red lava rock at the bottom of my media grow beds, about 4 to  6 inches and then top it with a about a 3 to 4 inch layer of 3/4 inch river rock and then either Hydroton or expended shale. Lave rock has excellent surface area for the bacteria to work but using it exclusively can be rough on the hands (somehow do not always have my gloves on when transplanting or cleaning/removing debris).

Love to see some current photos of your system. 

God bless :-)

 

[Converse]

 Thanks for the input.  I was thinking it (scoria) should be similar or the same across the board...but some of my Univ. geology classes information have gotten lost in the ancient and dusty reaches of my brain's filing system. Good to know about the recommendations.Yup, I'd been attracted to the idea of scoria due to the added surface area for bacterial growth.  Hope to get some photos of the AP systems up on our farm website when it is ready for the public.  Our kiddos are doing the photography ( part of our homeschooling curriculum) so we should have decent pictures - better than I could do.

   So now it is just a matter of shovelling and shovelling ...

   I am considering shovelling some of the regular basalt on top of the scoria to preserve our hands, as you have done, Sahib. But that may have to wait for another trip to the rock pile.

  Thank you for the information and pointers.