Well, the material that I have been running has no black sands, it's all garnet and granite sand. After many emails with the guys from GH it was determined that why I seen my mats running to clean was from the lack of heavy material ie: black sand. I'm going to a better place this weekend so I will know for sure. I do know I wish I had made my sluice wider, with how it's running, my water level is about 4", maybe a little to deep for the River Hog... I believe I'm not treating the "bed load" well enough and it may be flushing out. Once again, I'll know this weekend with better material.