Testing pH of Buildex Expanded Shale Pebbles

[Bill Moore]

One possible grow medium that might be considered somewhat comparable to Hydroton (expanded clay pebbles imported into the USA from Germany) is Buildex, an expanded shale product produced at a quarry located between St. Joseph, Mo. and Kansas City, which is only about 150 miles south of my location near Omaha, Ne.  The company sent me a 10 pound sample of the material to test. Today, after several weeks of letting a handful of the material sit in pH neutral snow melt (see attached photos), I tested the water.  As you can see, it is on the acidic side.  

[Conner Goertzen]

I live in Lincoln. Where can I purchase some Buildex to try? Apparently the pea gravel I purchased has too much limestone in it as the pH is still too high after almost a year.