Hi
I to like Kuhli loaches and have about 12 in my tank. I use Daltons aquatic mix about 1 and 1/2 inches and Daltons propagating sand 1 and 1/2 inches again (purchased from the warehouse and washed before use) because the tank is planted my loaches think they are hiding under the plants so they are always out and about. My plants also grow well.
Neill