So, I'm Planning this new set-up from scratch. a 75G with a "natural substrate (Sand over Peat, Redart Clay and sand mix). I was in the intro with the basic Idea which is in further development. So I have a question. Kuhli Loaches - How will they affect the substrate? I will be planning a variety of hidiong places in the set-up as I was going to have about 3 - 6 of them.