I think his leak is more like a drip than streams. I am not sure following the drifting sand would help in this case. I just dont think the flow through the leak is that dramatic.surnimensis;4336347; said:Right, I've a suggestion mate! I saw a documentry on ancient Egypt and more importantly water transfer foe crop iragation. The device used would often leek, hence this method used was to grab handfulls of fine sands and drop into the tank. The kiln dried sand would block the leek and transfer would continue. I thought u could use this method to locate your leek just follow the sand! It worked foe them cous!