I am from Pocatello and I have used local lava rock in both my 29 gal and 10 gal tanks. About 8 week ago I got some RCS for my 10 gal and they are just fine, In fact 2 are carrying eggs now and one has gave birth to about 35 babies. I have also had a group of 6 Amano Shrimp for over a year, it was 9 but I know my cat is responsible for 2 deaths. All my fish do fine. Some of my plants do great, some dont, but I think thats my fault not the lava rock. So I think that our Idaho lava rock is fine.