gdog, the way I add sand to an existin tank is to scoop up the sand in a cup and slowly lower the cup into the tank. This allows water to rush in and in doing it slowly will keep the sand in the cup. Then just pour it on the existing sand. Your water will get cloudy, but not as bad as if you just dump it in. I bought 10 pounds of GARF grunge. The only thing I liked about it was the rubble that came with it covered in several species of coralline, it made the tank look more natural. The thing I hated was the majority of the grunge was just that, pure grade A detritus. Clouded my tank for two days and it took a week to get it off all the rocks,corals, sand bed, and equip. I might, and I doubt it, but I might add it to a brand new tank before there is anything in it, but I would never again add it to an existing tank. HTH