I was under the impression those Hymilayan rocks wouldnt disolve in rain, but nope couple good rainstorms wash em away. I just nailed up the block hangers so they are just inside the barn over hang and out of the rain. Get the flavored ones from TSC, I wouldnt pay extra for the "natural " blocks. I bet they are pressed together in a mold in china anyways. I have white and the flavored red ones. The white one was hanging up forever was going to replace it with a flavored one, but I got back from an endurance ride and my horse bee lined for that white block. That told me he knew exactly where it was, knew what it was, and knew what he needed. It also told me he was probably getting plenty of electrolyte in his regular feed and grass. Now that it has been hot I noticed they are hitting it alot more.