I agree with Jenny- bark w/ maybe a little sphag, would be better. Catts. like light. Depending on your window position, I might move it to a window that gets sun most of the day. I live where that is needed, but maybe that would be too intense where you are. Have you grown with brick pieces before? If so, how has it worked for you? I received an orchid in a lava-rock type medium once, but I re-potted into a bark mix. It just seemed "warmer" for the plant roots.
