Repotting orchids
 

I would like to know if you can use red lava rock for your orchids that is used for landscape for flowers from lowes? Iwould like to try something different since it doesn't break down like bark does.

Yes. People have used Lava rock in the past. It seems kind of old school but it works for some plants.

As for use in Semi-Hydro I am not sure it would be that great.

Thanks. I would probably just pot some catteleya in it.

For Non-SH culture lava is great, heavier so pots don't tip over. I layer, lava at bottom of pot, LECA in middle and course hard bark at top. Works great, no rot. Avoid clay pots except for cool growers.