I use it Jeff. I didn’t want to deal with a deep sand bed in the display but wanted the benefits of the anaerobic bacteria. So, I made an acrylic 10”X4”X4” tray. Filled it with wet MM and then put a 1/4” if sand on top. I keep it in the sump where there’s low flow. I am guessing that is what helped get me to and maintain an ULNS before I had my current problems.